-<!doctype linuxdoc system>
+<!doctype linuxdoc system> <!-- -*- text-mode -*- -->
<article>
<title>ca65 Users Guide
-<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
-<date>19.07.2000, 29.11.2000, 02.10.2001
+<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
+<url url="mailto:greg.king5@verizon.net" name="Greg King">
<abstract>
-ca65 is a powerful macro assembler for the 6502, 65C02 and 65816 CPUs. It is
+ca65 is a powerful macro assembler for the 6502, 65C02, and 65816 CPUs. It is
used as a companion assembler for the cc65 crosscompiler, but it may also be
used as a standalone product.
</abstract>
---------------------------------------------------------------------------
Usage: ca65 [options] file
Short options:
- -D name[=value] Define a symbol
- -I dir Set an include directory search path
- -U Mark unresolved symbols as import
- -V Print the assembler version
- -W n Set warning level n
- -g Add debug info to object file
- -h Help (this text)
- -i Ignore case of symbols
- -l Create a listing if assembly was ok
- -o name Name the output file
- -s Enable smart mode
- -t sys Set the target system
- -v Increase verbosity
+ -D name[=value] Define a symbol
+ -I dir Set an include directory search path
+ -U Mark unresolved symbols as import
+ -V Print the assembler version
+ -W n Set warning level n
+ -d Debug mode
+ -g Add debug info to object file
+ -h Help (this text)
+ -i Ignore case of symbols
+ -l name Create a listing file if assembly was ok
+ -mm model Set the memory model
+ -o name Name the output file
+ -s Enable smart mode
+ -t sys Set the target system
+ -v Increase verbosity
Long options:
- --auto-import Mark unresolved symbols as import
- --cpu type Set cpu type
- --debug-info Add debug info to object file
- --feature name Set an emulation feature
- --help Help (this text)
- --ignore-case Ignore case of symbols
- --include-dir dir Set an include directory search path
- --listing Create a listing if assembly was ok
- --pagelength n Set the page length for the listing
- --smart Enable smart mode
- --target sys Set the target system
- --verbose Increase verbosity
- --version Print the assembler version
+ --auto-import Mark unresolved symbols as import
+ --bin-include-dir dir Set a search path for binary includes
+ --cpu type Set cpu type
+ --create-dep name Create a make dependency file
+ --create-full-dep name Create a full make dependency file
+ --debug Debug mode
+ --debug-info Add debug info to object file
+ --feature name Set an emulation feature
+ --help Help (this text)
+ --ignore-case Ignore case of symbols
+ --include-dir dir Set an include directory search path
+ --large-alignment Don't warn about large alignments
+ --listing name Create a listing file if assembly was ok
+ --list-bytes n Maximum number of bytes per listing line
+ --memory-model model Set the memory model
+ --pagelength n Set the page length for the listing
+ --relax-checks Relax some checks (see docs)
+ --smart Enable smart mode
+ --target sys Set the target system
+ --verbose Increase verbosity
+ --version Print the assembler version
---------------------------------------------------------------------------
</verb></tscreen>
<descrip>
+ <label id="option--bin-include-dir">
+ <tag><tt>--bin-include-dir dir</tt></tag>
+
+ Name a directory which is searched for binary include files. The option
+ may be used more than once to specify more than one directory to search. The
+ current directory is always searched first before considering any
+ additional directories. See also the section about <ref id="search-paths"
+ name="search paths">.
+
+
<label id="option--cpu">
<tag><tt>--cpu type</tt></tag>
Set the default for the CPU type. The option takes a parameter, which
may be one of
- 6502, 65SC02, 65C02, 65816 and sunplus
+ 6502, 6502X, 65SC02, 65C02, 65816, sweet16, HuC6280, 4510
+
+
+ <label id="option-create-dep">
+ <tag><tt>--create-dep name</tt></tag>
+
+ Tells the assembler to generate a file containing the dependency list for
+ the assembled module in makefile syntax. The output is written to a file
+ with the given name. The output does not include files passed via debug
+ information to the assembler.
+
- The last one (sunplus) is not available in the freeware version, because the
- instruction set of the sunplus CPU is "proprietary and confidential".
+ <label id="option-create-full-dep">
+ <tag><tt>--create-full-dep name</tt></tag>
+
+ Tells the assembler to generate a file containing the dependency list for
+ the assembled module in makefile syntax. The output is written to a file
+ with the given name. The output does include files passed via debug
+ information to the assembler.
+
+
+ <tag><tt>-d, --debug</tt></tag>
+
+ Enables debug mode, something that should not be needed for mere
+ mortals:-)
<label id="option--feature">
monitor.
+ <label id="option-h">
<tag><tt>-h, --help</tt></tag>
Print the short option summary shown above.
+ <label id="option-i">
<tag><tt>-i, --ignore-case</tt></tag>
This option makes the assembler case insensitive on identifiers and labels.
- This option will override the default, but may itself be overriden by the
+ This option will override the default, but may itself be overridden by the
<tt><ref id=".CASE" name=".CASE"></tt> control command.
- <tag><tt>-l, --listing</tt></tag>
+ <label id="option-l">
+ <tag><tt>-l name, --listing name</tt></tag>
+
+ Generate an assembler listing with the given name. A listing file will
+ never be generated in case of assembly errors.
+
+
+ <label id="option--large-alignment">
+ <tag><tt>--large-alignment</tt></tag>
+
+ Disable warnings about a large combined alignment. See the discussion of the
+ <tt><ref id=".ALIGN" name=".ALIGN"></tt> directive for futher information.
- Generate an assembler listing. The listing file will always have the
- name of the main input file with the extension replaced by ".lst". This
- may change in future versions.
+ <label id="option--list-bytes">
+ <tag><tt>--list-bytes n</tt></tag>
+ Set the maximum number of bytes printed in the listing for one line of
+ input. See the <tt><ref id=".LISTBYTES" name=".LISTBYTES"></tt> directive
+ for more information. The value zero can be used to encode an unlimited
+ number of printed bytes.
+
+
+ <label id="option-mm">
+ <tag><tt>-mm model, --memory-model model</tt></tag>
+
+ Define the default memory model. Possible model specifiers are near, far and
+ huge.
+
+
+ <label id="option-o">
<tag><tt>-o name</tt></tag>
The default output name is the name of the input file with the extension
the source file, or, if -o is given, the full path in this name is used.
+ <label id="option--pagelength">
<tag><tt>--pagelength n</tt></tag>
sets the length of a listing page in lines. See the <tt><ref
id=".PAGELENGTH" name=".PAGELENGTH"></tt> directive for more information.
+ <label id="option--relax-checks">
+ <tag><tt>--relax-checks</tt></tag>
+
+ Relax some checks done by the assembler. This will allow code that is an
+ error in most cases and flagged as such by the assembler, but can be valid
+ in special situations.
+
+ Examples are:
+<itemize>
+<item>Short branches between two different segments.
+<item>Byte sized address loads where the address is not a zeropage address.
+</itemize>
+
+
+ <label id="option-s">
<tag><tt>-s, --smart-mode</tt></tag>
In smart mode (enabled by -s or the <tt><ref id=".SMART" name=".SMART"></tt>
<label id="option-t">
<tag><tt>-t sys, --target sys</tt></tag>
- Set the target system. This will enable translation of character strings
- and character constants into the character set of the target platform.
- The default for the target system is "none", which means that no translation
+ Set the target system. This will enable translation of character strings and
+ character constants into the character set of the target platform. The
+ default for the target system is "none", which means that no translation
will take place. The assembler supports the same target systems as the
compiler, see there for a list.
+ Depending on the target, the default CPU type is also set. This can be
+ overriden by using the <tt/<ref id="option--cpu" name="--cpu">/ option.
+
+ <label id="option-v">
<tag><tt>-v, --verbose</tt></tag>
Increase the assembler verbosity. Usually only needed for debugging
verbose output.
+ <label id="option-D">
<tag><tt>-D</tt></tag>
This option allows you to define symbols on the command line. Without a
you may have to quote the expression.
+ <label id="option-I">
<tag><tt>-I dir, --include-dir dir</tt></tag>
Name a directory which is searched for include files. The option may be
used more than once to specify more than one directory to search. The
current directory is always searched first before considering any
- additional directores.
+ additional directories. See also the section about <ref id="search-paths"
+ name="search paths">.
+ <label id="option-U">
<tag><tt>-U, --auto-import</tt></tag>
Mark symbols that are not defined in the sources as imported symbols. This
which is not always true for assembler programmers.
+ <label id="option-V">
<tag><tt>-V, --version</tt></tag>
Print the version number of the assembler. If you send any suggestions
<p>
+
+<sect>Search paths<label id="search-paths"><p>
+
+Normal include files are searched in the following places:
+
+<enum>
+<item>The current file's directory.
+<item>Any directory added with the <tt/<ref id="option-I" name="-I">/ option
+on the command line.
+<item>The value of the environment variable <tt/CA65_INC/ if it is defined.
+<item>A subdirectory named <tt/asminc/ of the directory defined in the
+ environment variable <tt/CC65_HOME/, if it is defined.
+<item>An optionally compiled-in directory.
+</enum>
+
+Binary include files are searched in the following places:
+
+<enum>
+<item>The current file's directory.
+<item>Any directory added with the <tt/<ref id="option--bin-include-dir"
+name="--bin-include-dir">/ option on the command line.
+</enum>
+
+
+
<sect>Input format<p>
<sect1>Assembler syntax<p>
contain a label (which is identified by a colon), and, in addition to the
label, an assembler mnemonic, a macro, or a control command (see section <ref
id="control-commands" name="Control Commands"> for supported control
-commands). Alternatively, the line may contain a symbol definition using the
-'=' token. Everything after a semicolon is handled as a comment (that is, it
-is ignored).
+commands). Alternatively, the line may contain a symbol definition using
+the '=' token. Everything after a semicolon is handled as a comment (that is,
+it is ignored).
Here are some examples for valid input lines:
<itemize>
<item>all valid 6502 mnemonics when in 6502 mode (the default or after the
<tt><ref id=".P02" name=".P02"></tt> command was given).
+<item>all valid 6502 mnemonics plus a set of illegal instructions when in
+ <ref id="6502X-mode" name="6502X mode">.
<item>all valid 65SC02 mnemonics when in 65SC02 mode (after the
<tt><ref id=".PSC02" name=".PSC02"></tt> command was given).
<item>all valid 65C02 mnemonics when in 65C02 mode (after the
<tt><ref id=".PC02" name=".PC02"></tt> command was given).
-<item>all valid 65618 mnemonics when in 65816 mode (after the
+<item>all valid 65816 mnemonics when in 65816 mode (after the
<tt><ref id=".P816" name=".P816"></tt> command was given).
-<item>all valid SunPlus mnemonics when in SunPlus mode (after the
- <tt><ref id=".SUNPLUS" name=".SUNPLUS"></tt> command was given).
+<item>all valid 4510 mnemonics when in 4510 mode (after the
+ <tt><ref id=".P4510" name=".P4510"></tt> command was given).
</itemize>
<sect1>65816 mode<p>
-In 65816 mode several aliases are accepted in addition to the official
+In 65816 mode, several aliases are accepted, in addition to the official
mnemonics:
-<tscreen><verb>
- BGE is an alias for BCS
- BLT is an alias for BCC
- CPA is an alias for CMP
- DEA is an alias for DEC A
- INA is an alias for INC A
- SWA is an alias for XBA
- TAD is an alias for TCD
- TAS is an alias for TCS
- TDA is an alias for TDC
- TSA is an alias for TSC
-</verb></tscreen>
+<itemize>
+<item><tt>CPA</tt> is an alias for <tt>CMP</tt>
+<item><tt>DEA</tt> is an alias for <tt>DEC A</tt>
+<item><tt>INA</tt> is an alias for <tt>INC A</tt>
+<item><tt>SWA</tt> is an alias for <tt>XBA</tt>
+<item><tt>TAD</tt> is an alias for <tt>TCD</tt>
+<item><tt>TAS</tt> is an alias for <tt>TCS</tt>
+<item><tt>TDA</tt> is an alias for <tt>TDC</tt>
+<item><tt>TSA</tt> is an alias for <tt>TSC</tt>
+</itemize>
-Evaluation of banked expressions in 65816 mode differs slightly from the
-official syntax:
-Instead of accepting a 24 bit address (something that is difficult for
-the assembler to determine and would have required one more special
-.import command), the bank and the absolute address in that bank are
-separated by a dot:
+<sect1>6502X mode<label id="6502X-mode"><p>
+
+6502X mode is an extension to the normal 6502 mode. In this mode, several
+mnemonics for illegal instructions of the NMOS 6502 CPUs are accepted. Since
+these instructions are illegal, there are no official mnemonics for them. The
+unofficial ones are taken from <url
+url="http://www.oxyron.de/html/opcodes02.html">. Please note that only the
+ones marked as "stable" are supported. The following table uses information
+from the mentioned web page, for more information, see there.
+
+<itemize>
+<item><tt>ALR: A:=(A and #{imm})/2;</tt>
+<item><tt>ANC: A:=A and #{imm};</tt> Generates opcode $0B.
+<item><tt>ARR: A:=(A and #{imm})/2;</tt>
+<item><tt>AXS: X:=A and X-#{imm};</tt>
+<item><tt>DCP: {adr}:={adr}-1; A-{adr};</tt>
+<item><tt>ISC: {adr}:={adr}+1; A:=A-{adr};</tt>
+<item><tt>LAS: A,X,S:={adr} and S;</tt>
+<item><tt>LAX: A,X:={adr};</tt>
+<item><tt>RLA: {adr}:={adr}rol; A:=A and {adr};</tt>
+<item><tt>RRA: {adr}:={adr}ror; A:=A adc {adr};</tt>
+<item><tt>SAX: {adr}:=A and X;</tt>
+<item><tt>SLO: {adr}:={adr}*2; A:=A or {adr};</tt>
+<item><tt>SRE: {adr}:={adr}/2; A:=A xor {adr};</tt>
+</itemize>
+
+
+<sect1>4510 mode<p>
+
+The 4510 is a microcontroller that is the core of the Commodore C65 aka C64DX.
+It contains among other functions a slightly modified 65CE02/4502 CPU, to allow
+address mapping for 20 bits of address space (1 megabyte addressable area).
+As compared to the description of the CPU in the
+<url url="http://www.zimmers.net/anonftp/pub/cbm/c65/c65manualupdated.txt.gz"
+name="C65 System Specification">
+<url url="https://raw.githubusercontent.com/MEGA65/c65-specifications/master/c65manualupdated.txt"
+name="(updated version)"> uses these changes:
+<itemize>
+<item><tt>LDA (d,SP),Y</tt> may also be written as <tt>LDA (d,S),Y</tt>
+(matching the 65816 notataion).
+<item>All branch instruction allow now 16 bit offsets. To use a 16 bit
+branch you have to prefix these with an "L" (e.g. "<tt>LBNE</tt>" instead of
+"<tt>BNE</tt>"). This might change at a later implementation of the assembler.
+</itemize>
+For more information about the Commodore C65/C64DX and the 4510 CPU, see
+<url url="http://www.zimmers.net/anonftp/pub/cbm/c65/"> and
+<url url="https://en.wikipedia.org/wiki/Commodore_65" name="Wikipedia">.
+
+
+<sect1>sweet16 mode<label id="sweet16-mode"><p>
+
+SWEET 16 is an interpreter for a pseudo 16 bit CPU written by Steve Wozniak
+for the Apple ][ machines. It is available in the Apple ][ ROM. ca65 can
+generate code for this pseudo CPU when switched into sweet16 mode. The
+following is special in sweet16 mode:
+
+<itemize>
+
+<item>The '@' character denotes indirect addressing and is no longer available
+for cheap local labels. If you need cheap local labels, you will have to
+switch to another lead character using the <tt/<ref id=".LOCALCHAR"
+name=".LOCALCHAR">/ command.
+
+<item>Registers are specified using <tt/R0/ .. <tt/R15/. In sweet16 mode,
+these identifiers are reserved words.
+
+</itemize>
+
+Please note that the assembler does neither supply the interpreter needed for
+SWEET 16 code, nor the zero page locations needed for the SWEET 16 registers,
+nor does it call the interpreter. All this must be done by your program. Apple
+][ programmers do probably know how to use sweet16 mode.
+
+For more information about SWEET 16, see
+<url url="http://www.6502.org/source/interpreters/sweet16.htm">.
-<tscreen><verb>
- jsl 3.$1234 ; Call subroutine at $1234 in bank 3
-</verb></tscreen>
<sect1>Number format<p>
-For literal values, the assembler accepts the widely used number formats:
-A preceeding '$' denotes a hex value, a preceeding '%' denotes a
-binary value, and a bare number is interpeted as a decimal. There are
-currently no octal values and no floats.
+For literal values, the assembler accepts the widely used number formats: A
+preceding '$' or a trailing 'h' denotes a hex value, a preceding '%'
+denotes a binary value, and a bare number is interpreted as a decimal. There
+are currently no octal values and no floats.
<sect1>Conditional assembly<p>
<item> If the result of an expression is constant, the actual value is
checked to see if it's a byte sized expression or not.
<item> If the expression is explicitly casted to a byte sized expression by
- one of the '>'/'<' operators, it is a byte expression.
+ one of the '>', '<' or '^' operators, it is a byte expression.
<item> If this is not the case, and the expression contains a symbol,
explicitly declared as zero page symbol (by one of the .importzp or
.exportzp instructions), then the whole expression is assumed to be
<item> If the expression contains symbols that are not defined, and these
symbols are local symbols, the enclosing scopes are searched for a
symbol with the same name. If one exists and this symbol is defined,
- it's attributes are used to determine the result size.
+ its attributes are used to determine the result size.
<item> In all other cases the expression is assumed to be word sized.
</itemize>
In the context of a boolean expression, any non zero value is evaluated as
true, any other value to false. The result of a boolean expression is 1 if
-it's true, and zero if it's false. There are boolean operators with extrem
+it's true, and zero if it's false. There are boolean operators with extreme
low precedence with version 2.x (where x > 0). The <tt/.AND/ and <tt/.OR/
operators are shortcut operators. That is, if the result of the expression is
already known, after evaluating the left hand side, the right hand side is
<sect1>Available operators<label id="operators"><p>
-Available operators sorted by precedence:
-
-<tscreen><verb>
- Op Description Precedence
- -------------------------------------------------------------------
- .CONCAT Builtin function 0
- .LEFT Builtin function 0
- .MID Builtin function 0
- .RIGHT Builtin function 0
- .STRING Builtin function 0
-
- * Builtin pseudo variable (r/o) 1
- .BLANK Builtin function 1
- .CONST Builtin function 1
- .CPU Builtin pseudo variable (r/o) 1
- .DEFINED Builtin function 1
- .MATCH Builtin function 1
- .TCOUNT Builtin function 1
- .TIME Builtin function 1
- .VERSION Builtin function 1
- .XMATCH Builtin function 1
- .PARAMCOUNT Builtin pseudo variable (r/o) 1
- .REFERENCED Builtin function 1
- :: Global namespace override 1
- + Unary plus 1
- - Unary minus 1
- ~ Unary bitwise not 1
- .BITNOT Unary bitwise not 1
- < Low byte operator 1
- > High byte operator 1
- ^ Bank byte operator 1
-
- * Multiplication 2
- / Division 2
- .MOD Modulo operation 2
- & Bitwise and 2
- .BITAND Bitwise and 2
- ^ Bitwise xor 2
- .BITXOR Bitwise xor 2
- << Shift left operator 2
- .SHL Shift left operator 2
- >> Shift right operator
- .SHR Shift right operator 2
-
- + Binary plus 3
- - Binary minus 3
- | Binary or 3
- .BITOR Binary or 3
-
- = Compare operation (equal) 4
- <> Compare operation (not equal) 4
- < Compare operation (less) 4
- > Compare operation (greater) 4
- <= Compare operation (less or equal) 4
- >= Compare operation (greater or equal) 4
-
- && Boolean and 5
- .AND Boolean and 5
- .XOR Boolean xor 5
-
- || Boolean or 6
- .OR Boolean or 6
-
- ! Boolean not 7
- .NOT Boolean not 7
-</verb></tscreen>
-
-
-To force a specific order of evaluation, braces may be used as usual.
-
-Some of the pseudo variables mentioned above need some more explanation:
-
-<tscreen><verb>
- * This symbol is replaced by the value of the program
- counter at start of the current instruction. Note, that
- '*' yields a rvalue, that means, you cannot assign to it.
- Use <tt/.ORG/ to set the program counter in sections with
- absolute code.
-</verb></tscreen>
-<p>
+<table>
+<tabular ca="clc">
+<bf/Operator/| <bf/Description/| <bf/Precedence/@<hline>
+| Built-in string functions| 0@
+||~@
+| Built-in pseudo-variables| 1@
+| Built-in pseudo-functions| 1@
++| Unary positive| 1@
+-| Unary negative| 1@
+˜<newline>
+.BITNOT| Unary bitwise not| 1@
+<<newline>
+.LOBYTE| Unary low-byte operator| 1@
+><newline>
+.HIBYTE| Unary high-byte operator| 1@
+^<newline>
+.BANKBYTE| Unary bank-byte operator| 1@
+||~@
+*| Multiplication| 2@
+/| Division| 2@
+.MOD| Modulo operator| 2@
+&<newline>
+.BITAND| Bitwise and| 2@
+^<newline>
+.BITXOR| Binary bitwise xor| 2@
+<<<newline>
+.SHL| Shift-left operator| 2@
+>><newline>
+.SHR| Shift-right operator| 2@
+||~@
++| Binary addition| 3@
+-| Binary subtraction| 3@
+|<newline>
+.BITOR| Bitwise or| 3@
+||~@
+= | Compare operator (equal)| 4@
+<>| Compare operator (not equal)| 4@
+<| Compare operator (less)| 4@
+>| Compare operator (greater)| 4@
+<=| Compare operator (less or equal)| 4@
+>=| Compare operator (greater or equal)| 4@
+||~@
+&&<newline>
+.AND| Boolean and| 5@
+.XOR| Boolean xor| 5@
+||~@
+||<newline>
+.OR| Boolean or| 6@
+||~@
+!<newline>
+.NOT| Boolean not| 7@<hline>
+</tabular>
+<caption>Available operators, sorted by precedence
+</table>
+
+To force a specific order of evaluation, parentheses may be used, as usual.
<sect>Symbols and labels<p>
+A symbol or label is an identifier that starts with a letter and is followed
+by letters and digits. Depending on some features enabled (see
+<tt><ref id="at_in_identifiers" name="at_in_identifiers"></tt>,
+<tt><ref id="dollar_in_identifiers" name="dollar_in_identifiers"></tt> and
+<tt><ref id="leading_dot_in_identifiers" name="leading_dot_in_identifiers"></tt>)
+other characters may be present. Use of identifiers consisting of a single
+character will not work in all cases, because some of these identifiers are
+reserved keywords (for example "A" is not a valid identifier for a label,
+because it is the keyword for the accumulator).
+
The assembler allows you to use symbols instead of naked values to make
the source more readable. There are a lot of different ways to define and
use symbols and labels, giving a lot of flexibility.
-
<sect1>Numeric constants<p>
Numeric constants are defined using the equal sign or the label assignment
operator. After doing
<tscreen><verb>
- two = 2
+ two = 2
</verb></tscreen>
may use the symbol "two" in every place where a number is expected, and it is
-evaluated to the value 2 in this context. The label assignment operator causes
-the same, but causes the symbol to be marked as a label, which may cause a
-different handling in the debugger:
+evaluated to the value 2 in this context. The label assignment operator is
+almost identical, but causes the symbol to be marked as a label, so it may be
+handled differently in a debugger:
<tscreen><verb>
- io := $d000
+ io := $d000
</verb></tscreen>
The right side can of course be an expression:
<tscreen><verb>
- four = two * two
+ four = two * two
+</verb></tscreen>
+
+
+<label id="variables">
+<sect1>Numeric variables<p>
+
+Within macros and other control structures (<tt><ref id=".REPEAT"
+name=".REPEAT"></tt>, ...) it is sometimes useful to have some sort of
+variable. This can be achieved by the <tt>.SET</tt> operator. It creates a
+symbol that may get assigned a different value later:
+
+<tscreen><verb>
+ four .set 4
+ lda #four ; Loads 4 into A
+ four .set 3
+ lda #four ; Loads 3 into A
+</verb></tscreen>
+
+Since the value of the symbol can change later, it must be possible to
+evaluate it when used (no delayed evaluation as with normal symbols). So the
+expression used as the value must be constant.
+
+Following is an example for a macro that generates a different label each time
+it is used. It uses the <tt><ref id=".SPRINTF" name=".SPRINTF"></tt> function
+and a numeric variable named <tt>lcount</tt>.
+
+<tscreen><verb>
+ .lcount .set 0 ; Initialize the counter
+
+ .macro genlab
+ .ident (.sprintf ("L%04X", lcount)):
+ lcount .set lcount + 1
+ .endmacro
</verb></tscreen>
changed by the <tt><ref id=".LOCALCHAR" name=".LOCALCHAR"></tt>
directive).
-Cheap local labels are visible only between two non cheap labels. As soon as a
-standard symbol is encountered (this may also be a local symbol if inside a
-region defined with the <tt><ref id=".PROC" name=".PROC"></tt> directive), the
-cheap local symbol goes out of scope.
+Cheap local labels are visible only between two non cheap labels. As soon as a
+standard symbol is encountered (this may also be a local symbol if inside a
+region defined with the <tt><ref id=".PROC" name=".PROC"></tt> directive), the
+cheap local symbol goes out of scope.
+
+You may use cheap local labels as an easy way to reuse common label
+names like "Loop". Here is an example:
+
+<tscreen><verb>
+ Clear: lda #$00 ; Global label
+ ldy #$20
+ @Loop: sta Mem,y ; Local label
+ dey
+ bne @Loop ; Ok
+ rts
+ Sub: ... ; New global label
+ bne @Loop ; ERROR: Unknown identifier!
+</verb></tscreen>
+
+<sect1>Unnamed labels<p>
+
+If you really want to write messy code, there are also unnamed labels. These
+labels do not have a name (you guessed that already, didn't you?). A colon is
+used to mark the absence of the name.
+
+Unnamed labels may be accessed by using the colon plus several minus or plus
+characters as a label designator. Using the '-' characters will create a back
+reference (use the n'th label backwards), using '+' will create a forward
+reference (use the n'th label in forward direction). An example will help to
+understand this:
+
+<tscreen><verb>
+ : lda (ptr1),y ; #1
+ cmp (ptr2),y
+ bne :+ ; -> #2
+ tax
+ beq :+++ ; -> #4
+ iny
+ bne :- ; -> #1
+ inc ptr1+1
+ inc ptr2+1
+ bne :- ; -> #1
+
+ : bcs :+ ; #2 -> #3
+ ldx #$FF
+ rts
+
+ : ldx #$01 ; #3
+ : rts ; #4
+</verb></tscreen>
+
+As you can see from the example, unnamed labels will make even short
+sections of code hard to understand, because you have to count labels
+to find branch targets (this is the reason why I for my part do
+prefer the "cheap" local labels). Nevertheless, unnamed labels are
+convenient in some situations, so it's your decision.
+
+<em/Note:/ <ref id="scopes" name="Scopes"> organize named symbols, not
+unnamed ones, so scopes don't have an effect on unnamed labels.
+
+
+
+<sect1>Using macros to define labels and constants<p>
+
+While there are drawbacks with this approach, it may be handy in a few rare
+situations. Using <tt><ref id=".DEFINE" name=".DEFINE"></tt>, it is possible
+to define symbols or constants that may be used elsewhere. One of the
+advantages is that you can use it to define string constants (this is not
+possible with the other symbol types).
+
+Please note: <tt/.DEFINE/ style macros do token replacements on a low level,
+so the names do not adhere to scoping, diagnostics may be misleading, there
+are no symbols to look up in the map file, and there is no debug info.
+Especially the first problem in the list can lead to very nasty programming
+errors. Because of these problems, the general advice is, <bf/NOT/ do use
+<tt/.DEFINE/ if you don't have to.
+
+Example:
+
+<tscreen><verb>
+ .DEFINE two 2
+ .DEFINE version "SOS V2.3"
+
+ four = two * two ; Ok
+ .byte version ; Ok
+
+ .PROC ; Start local scope
+ two = 3 ; Will give "2 = 3" - invalid!
+ .ENDPROC
+</verb></tscreen>
+
+
+<sect1>Symbols and <tt>.DEBUGINFO</tt><p>
+
+If <tt><ref id=".DEBUGINFO" name=".DEBUGINFO"></tt> is enabled (or <ref
+id="option-g" name="-g"> is given on the command line), global, local and
+cheap local labels are written to the object file and will be available in the
+symbol file via the linker. Unnamed labels are not written to the object file,
+because they don't have a name which would allow to access them.
+
+
+
+<sect>Scopes<label id="scopes"><p>
+
+ca65 implements several sorts of scopes for symbols.
+
+<sect1>Global scope<p>
+
+All (non cheap local) symbols that are declared outside of any nested scopes
+are in global scope.
+
+
+<sect1>Cheap locals<p>
+
+A special scope is the scope for cheap local symbols. It lasts from one non
+local symbol to the next one, without any provisions made by the programmer.
+All other scopes differ in usage but use the same concept internally.
+
+
+<sect1>Generic nested scopes<p>
+
+A nested scoped for generic use is started with <tt/<ref id=".SCOPE"
+name=".SCOPE">/ and closed with <tt/<ref id=".ENDSCOPE" name=".ENDSCOPE">/.
+The scope can have a name, in which case it is accessible from the outside by
+using <ref id="scopesyntax" name="explicit scopes">. If the scope does not
+have a name, all symbols created within the scope are local to the scope, and
+aren't accessible from the outside.
+
+A nested scope can access symbols from the local or from enclosing scopes by
+name without using explicit scope names. In some cases there may be
+ambiguities, for example if there is a reference to a local symbol that is not
+yet defined, but a symbol with the same name exists in outer scopes:
+
+<tscreen><verb>
+ .scope outer
+ foo = 2
+ .scope inner
+ lda #foo
+ foo = 3
+ .endscope
+ .endscope
+</verb></tscreen>
+
+In the example above, the <tt/lda/ instruction will load the value 3 into the
+accumulator, because <tt/foo/ is redefined in the scope. However:
+
+<tscreen><verb>
+ .scope outer
+ foo = $1234
+ .scope inner
+ lda foo,x
+ foo = $12
+ .endscope
+ .endscope
+</verb></tscreen>
+
+Here, <tt/lda/ will still load from <tt/$12,x/, but since it is unknown to the
+assembler that <tt/foo/ is a zeropage symbol when translating the instruction,
+absolute mode is used instead. In fact, the assembler will not use absolute
+mode by default, but it will search through the enclosing scopes for a symbol
+with the given name. If one is found, the address size of this symbol is used.
+This may lead to errors:
+
+<tscreen><verb>
+ .scope outer
+ foo = $12
+ .scope inner
+ lda foo,x
+ foo = $1234
+ .endscope
+ .endscope
+</verb></tscreen>
+
+In this case, when the assembler sees the symbol <tt/foo/ in the <tt/lda/
+instruction, it will search for an already defined symbol <tt/foo/. It will
+find <tt/foo/ in scope <tt/outer/, and a close look reveals that it is a
+zeropage symbol. So the assembler will use zeropage addressing mode. If
+<tt/foo/ is redefined later in scope <tt/inner/, the assembler tries to change
+the address in the <tt/lda/ instruction already translated, but since the new
+value needs absolute addressing mode, this fails, and an error message "Range
+error" is output.
+
+Of course the most simple solution for the problem is to move the definition
+of <tt/foo/ in scope <tt/inner/ upwards, so it precedes its use. There may be
+rare cases when this cannot be done. In these cases, you can use one of the
+address size override operators:
+
+<tscreen><verb>
+ .scope outer
+ foo = $12
+ .scope inner
+ lda a:foo,x
+ foo = $1234
+ .endscope
+ .endscope
+</verb></tscreen>
+
+This will cause the <tt/lda/ instruction to be translated using absolute
+addressing mode, which means changing the symbol reference later does not
+cause any errors.
+
+
+<sect1>Nested procedures<p>
+
+A nested procedure is created by use of <tt/<ref id=".PROC" name=".PROC">/. It
+differs from a <tt/<ref id=".SCOPE" name=".SCOPE">/ in that it must have a
+name, and a it will introduce a symbol with this name in the enclosing scope.
+So
+
+<tscreen><verb>
+ .proc foo
+ ...
+ .endproc
+</verb></tscreen>
+
+is actually the same as
+
+<tscreen><verb>
+ foo:
+ .scope foo
+ ...
+ .endscope
+</verb></tscreen>
+
+This is the reason why a procedure must have a name. If you want a scope
+without a name, use <tt/<ref id=".SCOPE" name=".SCOPE">/.
+
+<em/Note:/ As you can see from the example above, scopes and symbols live in
+different namespaces. There can be a symbol named <tt/foo/ and a scope named
+<tt/foo/ without any conflicts (but see the section titled <ref
+id="scopesearch" name=""Scope search order"">).
+
+
+<sect1>Structs, unions and enums<p>
+
+Structs, unions and enums are explained in a <ref id="structs" name="separate
+section">, I do only cover them here, because if they are declared with a
+name, they open a nested scope, similar to <tt/<ref id=".SCOPE"
+name=".SCOPE">/. However, when no name is specified, the behaviour is
+different: In this case, no new scope will be opened, symbols declared within
+a struct, union, or enum declaration will then be added to the enclosing scope
+instead.
+
+
+<sect1>Explicit scope specification<label id="scopesyntax"><p>
+
+Accessing symbols from other scopes is possible by using an explicit scope
+specification, provided that the scope where the symbol lives in has a name.
+The namespace token (<tt/::/) is used to access other scopes:
+
+<tscreen><verb>
+ .scope foo
+ bar: .word 0
+ .endscope
+
+ ...
+ lda foo::bar ; Access foo in scope bar
+</verb></tscreen>
+
+The only way to deny access to a scope from the outside is to declare a scope
+without a name (using the <tt/<ref id=".SCOPE" name=".SCOPE">/ command).
+
+A special syntax is used to specify the global scope: If a symbol or scope is
+preceded by the namespace token, the global scope is searched:
+
+<tscreen><verb>
+ bar = 3
+
+ .scope foo
+ bar = 2
+ lda #::bar ; Access the global bar (which is 3)
+ .endscope
+</verb></tscreen>
+
+
+<sect1>Scope search order<label id="scopesearch"><p>
+
+The assembler searches for a scope in a similar way as for a symbol. First, it
+looks in the current scope, and then it walks up the enclosing scopes until
+the scope is found.
+
+However, one important thing to note when using explicit scope syntax is, that
+a symbol may be accessed before it is defined, but a scope may <bf/not/ be
+used without a preceding definition. This means that in the following
+example:
+
+<tscreen><verb>
+ .scope foo
+ bar = 3
+ .endscope
+
+ .scope outer
+ lda #foo::bar ; Will load 3, not 2!
+ .scope foo
+ bar = 2
+ .endscope
+ .endscope
+</verb></tscreen>
+
+the reference to the scope <tt/foo/ will use the global scope, and not the
+local one, because the local one is not visible at the point where it is
+referenced.
+
+Things get more complex if a complete chain of scopes is specified:
+
+<tscreen><verb>
+ .scope foo
+ .scope outer
+ .scope inner
+ bar = 1
+ .endscope
+ .endscope
+ .scope another
+ .scope nested
+ lda #outer::inner::bar ; 1
+ .endscope
+ .endscope
+ .endscope
+
+ .scope outer
+ .scope inner
+ bar = 2
+ .endscope
+ .endscope
+</verb></tscreen>
+
+When <tt/outer::inner::bar/ is referenced in the <tt/lda/ instruction, the
+assembler will first search in the local scope for a scope named <tt/outer/.
+Since none is found, the enclosing scope (<tt/another/) is checked. There is
+still no scope named <tt/outer/, so scope <tt/foo/ is checked, and finally
+scope <tt/outer/ is found. Within this scope, <tt/inner/ is searched, and in
+this scope, the assembler looks for a symbol named <tt/bar/.
+
+Please note that once the anchor scope is found, all following scopes
+(<tt/inner/ in this case) are expected to be found exactly in this scope. The
+assembler will search the scope tree only for the first scope (if it is not
+anchored in the root scope). Starting from there on, there is no flexibility,
+so if the scope named <tt/outer/ found by the assembler does not contain a
+scope named <tt/inner/, this would be an error, even if such a pair does exist
+(one level up in global scope).
+
+Ambiguities that may be introduced by this search algorithm may be removed by
+anchoring the scope specification in the global scope. In the example above,
+if you want to access the "other" symbol <tt/bar/, you would have to write:
+
+<tscreen><verb>
+ .scope foo
+ .scope outer
+ .scope inner
+ bar = 1
+ .endscope
+ .endscope
+ .scope another
+ .scope nested
+ lda #::outer::inner::bar ; 2
+ .endscope
+ .endscope
+ .endscope
+
+ .scope outer
+ .scope inner
+ bar = 2
+ .endscope
+ .endscope
+</verb></tscreen>
+
+
+<sect>Address sizes and memory models<label id="address-sizes"><p>
+
+<sect1>Address sizes<p>
+
+ca65 assigns each segment and each symbol an address size. This is true, even
+if the symbol is not used as an address. You may also think of a value range
+of the symbol instead of an address size.
+
+Possible address sizes are:
+
+<itemize>
+<item>Zeropage or direct (8 bits)
+<item>Absolute (16 bits)
+<item>Far (24 bits)
+<item>Long (32 bits)
+</itemize>
+
+Since the assembler uses default address sizes for the segments and symbols,
+it is usually not necessary to override the default behaviour. In cases, where
+it is necessary, the following keywords may be used to specify address sizes:
+
+<itemize>
+<item>DIRECT, ZEROPAGE or ZP for zeropage addressing (8 bits).
+<item>ABSOLUTE, ABS or NEAR for absolute addressing (16 bits).
+<item>FAR for far addressing (24 bits).
+<item>LONG or DWORD for long addressing (32 bits).
+</itemize>
+
+
+<sect1>Address sizes of segments<p>
+
+The assembler assigns an address size to each segment. Since the
+representation of a label within this segment is "segment start + offset",
+labels will inherit the address size of the segment they are declared in.
+
+The address size of a segment may be changed, by using an optional address
+size modifier. See the <tt/<ref id=".SEGMENT" name="segment directive">/ for
+an explanation on how this is done.
+
+
+<sect1>Address sizes of symbols<p>
+
+The address size of a symbol can be specified with a prefix:
+
+<itemize>
+<item>z: zeropage addressing (8 bits).
+<item>a: absolute addressing (16 bits).
+<item>f: far addressing (24 bits).
+</itemize>
+
+The zeropage addressing override can be used to ensure the use of optimal
+zeropage instructions, or correct cases where the size isn't yet known
+due to the single-pass assembly model.
+
+The larger addressing overrides can be used to promote a smaller address
+to absolute or far addressing, instead of being automatically fit into
+a smaller addressing type.
+
+
+<sect1>Memory models<p>
+
+The default address size of a segment depends on the memory model used. Since
+labels inherit the address size from the segment they are declared in,
+changing the memory model is an easy way to change the address size of many
+symbols at once.
+
+
+
+
+<sect>Pseudo variables<label id="pseudo-variables"><p>
+
+Pseudo variables are readable in all cases, and in some special cases also
+writable.
+
+<sect1><tt>*</tt><p>
+
+ Reading this pseudo variable will return the program counter at the start
+ of the current input line.
+
+ Assignment to this variable is possible when <tt/<ref id=".FEATURE"
+ name=".FEATURE pc_assignment">/ is used. Note: You should not use
+ assignments to <tt/*/, use <tt/<ref id=".ORG" name=".ORG">/ instead.
+
+
+<sect1><tt>.ASIZE</tt><label id=".ASIZE"><p>
+
+ Reading this pseudo variable will return the current size of the
+ Accumulator in bits.
+
+ For the 65816 instruction set .ASIZE will return either 8 or 16, depending
+ on the current size of the operand in immediate accu addressing mode.
+
+ For all other CPU instruction sets, .ASIZE will always return 8.
+
+ Example:
+
+ <tscreen><verb>
+ ; Reverse Subtract with Accumulator
+ ; A = memory - A
+ .macro rsb param
+ .if .asize = 8
+ eor #$ff
+ .else
+ eor #$ffff
+ .endif
+ sec
+ adc param
+ .endmacro
+ </verb></tscreen>
+
+ See also: <tt><ref id=".ISIZE" name=".ISIZE"></tt>
+
+
+<sect1><tt>.CPU</tt><label id=".CPU"><p>
+
+ Reading this pseudo variable will give a constant integer value that
+ tells which CPU is currently enabled. It can also tell which instruction
+ set the CPU is able to translate. The value read from the pseudo variable
+ should be further examined by using one of the constants defined by the
+ "cpu" macro package (see <tt/<ref id=".MACPACK" name=".MACPACK">/).
+
+ It may be used to replace the .IFPxx pseudo instructions or to construct
+ even more complex expressions.
+
+ Example:
+
+ <tscreen><verb>
+ .macpack cpu
+ .if (.cpu .bitand CPU_ISET_65816)
+ phx
+ phy
+ .else
+ txa
+ pha
+ tya
+ pha
+ .endif
+ </verb></tscreen>
+
+
+<sect1><tt>.ISIZE</tt><label id=".ISIZE"><p>
+
+ Reading this pseudo variable will return the current size of the Index
+ register in bits.
+
+ For the 65816 instruction set .ISIZE will return either 8 or 16, depending
+ on the current size of the operand in immediate index addressing mode.
+
+ For all other CPU instruction sets, .ISIZE will always return 8.
+
+ See also: <tt><ref id=".ASIZE" name=".ASIZE"></tt>
+
+
+<sect1><tt>.PARAMCOUNT</tt><label id=".PARAMCOUNT"><p>
+
+ This builtin pseudo variable is only available in macros. It is replaced by
+ the actual number of parameters that were given in the macro invocation.
+
+ Example:
+
+ <tscreen><verb>
+ .macro foo arg1, arg2, arg3
+ .if .paramcount <> 3
+ .error "Too few parameters for macro foo"
+ .endif
+ ...
+ .endmacro
+ </verb></tscreen>
+
+ See section <ref id="macros" name="Macros">.
+
+
+<sect1><tt>.TIME</tt><label id=".TIME"><p>
+
+ Reading this pseudo variable will give a constant integer value that
+ represents the current time in POSIX standard (as seconds since the
+ Epoch).
+
+ It may be used to encode the time of translation somewhere in the created
+ code.
+
+ Example:
+
+ <tscreen><verb>
+ .dword .time ; Place time here
+ </verb></tscreen>
+
+
+<sect1><tt>.VERSION</tt><label id=".VERSION"><p>
+
+ Reading this pseudo variable will give the assembler version according to
+ the following formula:
+
+ VER_MAJOR*$100 + VER_MINOR*$10
+
+ It may be used to encode the assembler version or check the assembler for
+ special features not available with older versions.
+
+ Example:
+
+ Version 2.14 of the assembler will return $2E0 as numerical constant when
+ reading the pseudo variable <tt/.VERSION/.
+
+
+
+<sect>Pseudo functions<label id="pseudo-functions"><p>
+
+Pseudo functions expect their arguments in parenthesis, and they have a result,
+either a string or an expression.
+
+
+<sect1><tt>.ADDRSIZE</tt><label id=".ADDRSIZE"><p>
+
+ The <tt/.ADDRSIZE/ function is used to return the interal address size
+ associated with a symbol. This can be helpful in macros when knowing the address
+ size of symbol can help with custom instructions.
+
+ Example:
+
+ <tscreen><verb>
+ .macro myLDA foo
+ .if .ADDRSIZE(foo) = 1
+ ;do custom command based on zeropage addressing:
+ .byte 0A5h, foo
+ .elseif .ADDRSIZE(foo) = 2
+ ;do custom command based on absolute addressing:
+ .byte 0ADh
+ .word foo
+ .elseif .ADDRSIZE(foo) = 0
+ ; no address size defined for this symbol:
+ .out .sprintf("Error, address size unknown for symbol %s", .string(foo))
+ .endif
+ .endmacro
+ </verb></tscreen>
+
+ This command is new and must be enabled with the <tt/.FEATURE addrsize/ command.
+
+ See: <tt><ref id=".FEATURE" name=".FEATURE"></tt>
+
+
+<sect1><tt>.BANK</tt><label id=".BANK"><p>
+
+ The <tt/.BANK/ function is used to support systems with banked memory. The
+ argument is an expression with exactly one segment reference - usually a
+ label. The function result is the value of the <tt/bank/ attribute assigned
+ to the run memory area of the segment. Please see the linker documentation
+ for more information about memory areas and their attributes.
+
+ The value of <tt/.BANK/ can be used to switch memory so that a memory bank
+ containing specific data is available.
+
+ The <tt/bank/ attribute is a 32 bit integer and so is the result of the
+ <tt/.BANK/ function. You will have to use <tt><ref id=".LOBYTE"
+ name=".LOBYTE"></tt> or similar functions to address just part of it.
+
+ Please note that <tt/.BANK/ will always get evaluated in the link stage, so
+ an expression containing <tt/.BANK/ can never be used where a constant known
+ result is expected (for example with <tt/.RES/).
+
+ Example:
+
+ <tscreen><verb>
+ .segment "BANK1"
+ .proc banked_func_1
+ ...
+ .endproc
+
+ .segment "BANK2"
+ .proc banked_func_2
+ ...
+ .endproc
+
+ .proc bank_table
+ .addr banked_func_1
+ .byte <.BANK (banked_func_1)
+
+ .addr banked_func_2
+ .byte <.BANK (banked_func_2)
+ .endproc
+ </verb></tscreen>
+
+
+
+<sect1><tt>.BANKBYTE</tt><label id=".BANKBYTE"><p>
+
+ The function returns the bank byte (that is, bits 16-23) of its argument.
+ It works identical to the '^' operator.
+
+ See: <tt><ref id=".HIBYTE" name=".HIBYTE"></tt>,
+ <tt><ref id=".LOBYTE" name=".LOBYTE"></tt>
+
+
+<sect1><tt>.BLANK</tt><label id=".BLANK"><p>
+
+ Builtin function. The function evaluates its argument in braces and yields
+ "false" if the argument is non blank (there is an argument), and "true" if
+ there is no argument. The token list that makes up the function argument
+ may optionally be enclosed in curly braces. This allows the inclusion of
+ tokens that would otherwise terminate the list (the closing right
+ parenthesis). The curly braces are not considered part of the list, a list
+ just consisting of curly braces is considered to be empty.
+
+ As an example, the <tt/.IFBLANK/ statement may be replaced by
+
+ <tscreen><verb>
+ .if .blank({arg})
+ </verb></tscreen>
+
+
+
+<sect1><tt>.CONCAT</tt><label id=".CONCAT"><p>
+
+ Builtin string function. The function allows to concatenate a list of string
+ constants separated by commas. The result is a string constant that is the
+ concatenation of all arguments. This function is most useful in macros and
+ when used together with the <tt/.STRING/ builtin function. The function may
+ be used in any case where a string constant is expected.
+
+ Example:
+
+ <tscreen><verb>
+ .include .concat ("myheader", ".", "inc")
+ </verb></tscreen>
+
+ This is the same as the command
+
+ <tscreen><verb>
+ .include "myheader.inc"
+ </verb></tscreen>
+
+
+<sect1><tt>.CONST</tt><label id=".CONST"><p>
+
+ Builtin function. The function evaluates its argument in braces and
+ yields "true" if the argument is a constant expression (that is, an
+ expression that yields a constant value at assembly time) and "false"
+ otherwise. As an example, the .IFCONST statement may be replaced by
+
+ <tscreen><verb>
+ .if .const(a + 3)
+ </verb></tscreen>
+
+
+<sect1><tt>.HIBYTE</tt><label id=".HIBYTE"><p>
+
+ The function returns the high byte (that is, bits 8-15) of its argument.
+ It works identical to the '>' operator.
+
+ See: <tt><ref id=".LOBYTE" name=".LOBYTE"></tt>,
+ <tt><ref id=".BANKBYTE" name=".BANKBYTE"></tt>
+
+
+<sect1><tt>.HIWORD</tt><label id=".HIWORD"><p>
+
+ The function returns the high word (that is, bits 16-31) of its argument.
+
+ See: <tt><ref id=".LOWORD" name=".LOWORD"></tt>
+
+
+<sect1><tt>.IDENT</tt><label id=".IDENT"><p>
+
+ The function expects a string as its argument, and converts this argument
+ into an identifier. If the string starts with the current <tt/<ref
+ id=".LOCALCHAR" name=".LOCALCHAR">/, it will be converted into a cheap local
+ identifier, otherwise it will be converted into a normal identifier.
+
+ Example:
+
+ <tscreen><verb>
+ .macro makelabel arg1, arg2
+ .ident (.concat (arg1, arg2)):
+ .endmacro
+
+ makelabel "foo", "bar"
+
+ .word foobar ; Valid label
+ </verb></tscreen>
+
+
+<sect1><tt>.LEFT</tt><label id=".LEFT"><p>
+
+ Builtin function. Extracts the left part of a given token list.
+
+ Syntax:
+
+ <tscreen><verb>
+ .LEFT (<int expr>, <token list>)
+ </verb></tscreen>
+
+ The first integer expression gives the number of tokens to extract from
+ the token list. The second argument is the token list itself. The token
+ list may optionally be enclosed into curly braces. This allows the
+ inclusion of tokens that would otherwise terminate the list (the closing
+ right paren in the given case).
+
+ Example:
+
+ To check in a macro if the given argument has a '#' as first token
+ (immediate addressing mode), use something like this:
+
+ <tscreen><verb>
+ .macro ldax arg
+ ...
+ .if (.match (.left (1, {arg}), #))
+
+ ; ldax called with immediate operand
+ ...
+
+ .endif
+ ...
+ .endmacro
+ </verb></tscreen>
+
+ See also the <tt><ref id=".MID" name=".MID"></tt> and <tt><ref id=".RIGHT"
+ name=".RIGHT"></tt> builtin functions.
+
+
+<sect1><tt>.LOBYTE</tt><label id=".LOBYTE"><p>
+
+ The function returns the low byte (that is, bits 0-7) of its argument.
+ It works identical to the '<' operator.
+
+ See: <tt><ref id=".HIBYTE" name=".HIBYTE"></tt>,
+ <tt><ref id=".BANKBYTE" name=".BANKBYTE"></tt>
+
+
+<sect1><tt>.LOWORD</tt><label id=".LOWORD"><p>
+
+ The function returns the low word (that is, bits 0-15) of its argument.
+
+ See: <tt><ref id=".HIWORD" name=".HIWORD"></tt>
+
+
+<sect1><tt>.MATCH</tt><label id=".MATCH"><p>
+
+ Builtin function. Matches two token lists against each other. This is
+ most useful within macros, since macros are not stored as strings, but
+ as lists of tokens.
+
+ The syntax is
+
+ <tscreen><verb>
+ .MATCH(<token list #1>, <token list #2>)
+ </verb></tscreen>
+
+ Both token list may contain arbitrary tokens with the exception of the
+ terminator token (comma resp. right parenthesis) and
+
+ <itemize>
+ <item>end-of-line
+ <item>end-of-file
+ </itemize>
+
+ The token lists may optionally be enclosed into curly braces. This allows
+ the inclusion of tokens that would otherwise terminate the list (the closing
+ right paren in the given case). Often a macro parameter is used for any of
+ the token lists.
+
+ Please note that the function does only compare tokens, not token
+ attributes. So any number is equal to any other number, regardless of the
+ actual value. The same is true for strings. If you need to compare tokens
+ <em/and/ token attributes, use the <tt><ref id=".XMATCH"
+ name=".XMATCH"></tt> function.
+
+ Example:
+
+ Assume the macro <tt/ASR/, that will shift right the accumulator by one,
+ while honoring the sign bit. The builtin processor instructions will allow
+ an optional "A" for accu addressing for instructions like <tt/ROL/ and
+ <tt/ROR/. We will use the <tt><ref id=".MATCH" name=".MATCH"></tt> function
+ to check for this and print and error for invalid calls.
+
+ <tscreen><verb>
+ .macro asr arg
+
+ .if (.not .blank(arg)) .and (.not .match ({arg}, a))
+ .error "Syntax error"
+ .endif
+
+ cmp #$80 ; Bit 7 into carry
+ lsr a ; Shift carry into bit 7
+
+ .endmacro
+ </verb></tscreen>
+
+ The macro will only accept no arguments, or one argument that must be the
+ reserved keyword "A".
+
+ See: <tt><ref id=".XMATCH" name=".XMATCH"></tt>
+
+
+<sect1><tt>.MAX</tt><label id=".MAX"><p>
+
+ Builtin function. The result is the larger of two values.
+
+ The syntax is
+
+ <tscreen><verb>
+ .MAX (<value #1>, <value #2>)
+ </verb></tscreen>
+
+ Example:
+
+ <tscreen><verb>
+ ; Reserve space for the larger of two data blocks
+ savearea: .res .max (.sizeof (foo), .sizeof (bar))
+ </verb></tscreen>
+
+ See: <tt><ref id=".MIN" name=".MIN"></tt>
+
+
+<sect1><tt>.MID</tt><label id=".MID"><p>
+
+ Builtin function. Takes a starting index, a count and a token list as
+ arguments. Will return part of the token list.
+
+ Syntax:
+
+ <tscreen><verb>
+ .MID (<int expr>, <int expr>, <token list>)
+ </verb></tscreen>
+
+ The first integer expression gives the starting token in the list (the first
+ token has index 0). The second integer expression gives the number of tokens
+ to extract from the token list. The third argument is the token list itself.
+ The token list may optionally be enclosed into curly braces. This allows the
+ inclusion of tokens that would otherwise terminate the list (the closing
+ right paren in the given case).
+
+ Example:
+
+ To check in a macro if the given argument has a '<tt/#/' as first token
+ (immediate addressing mode), use something like this:
+
+ <tscreen><verb>
+ .macro ldax arg
+ ...
+ .if (.match (.mid (0, 1, {arg}), #))
+
+ ; ldax called with immediate operand
+ ...
+
+ .endif
+ ...
+ .endmacro
+ </verb></tscreen>
+
+ See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".RIGHT"
+ name=".RIGHT"></tt> builtin functions.
+
+
+<sect1><tt>.MIN</tt><label id=".MIN"><p>
+
+ Builtin function. The result is the smaller of two values.
+
+ The syntax is
+
+ <tscreen><verb>
+ .MIN (<value #1>, <value #2>)
+ </verb></tscreen>
+
+ Example:
+
+ <tscreen><verb>
+ ; Reserve space for some data, but 256 bytes maximum
+ savearea: .res .min (.sizeof (foo), 256)
+ </verb></tscreen>
+
+ See: <tt><ref id=".MAX" name=".MAX"></tt>
+
+
+<sect1><tt>.REF, .REFERENCED</tt><label id=".REFERENCED"><p>
+
+ Builtin function. The function expects an identifier as argument in braces.
+ The argument is evaluated, and the function yields "true" if the identifier
+ is a symbol that has already been referenced somewhere in the source file up
+ to the current position. Otherwise the function yields false. As an example,
+ the <tt><ref id=".IFREF" name=".IFREF"></tt> statement may be replaced by
+
+ <tscreen><verb>
+ .if .referenced(a)
+ </verb></tscreen>
+
+ See: <tt><ref id=".DEFINED" name=".DEFINED"></tt>
+
+
+<sect1><tt>.RIGHT</tt><label id=".RIGHT"><p>
+
+ Builtin function. Extracts the right part of a given token list.
+
+ Syntax:
+
+ <tscreen><verb>
+ .RIGHT (<int expr>, <token list>)
+ </verb></tscreen>
+
+ The first integer expression gives the number of tokens to extract from the
+ token list. The second argument is the token list itself. The token list
+ may optionally be enclosed into curly braces. This allows the inclusion of
+ tokens that would otherwise terminate the list (the closing right paren in
+ the given case).
+
+ See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".MID"
+ name=".MID"></tt> builtin functions.
+
+
+<sect1><tt>.SIZEOF</tt><label id=".SIZEOF"><p>
+
+ <tt/.SIZEOF/ is a pseudo function that returns the size of its argument. The
+ argument can be a struct/union, a struct member, a procedure, or a label. In
+ case of a procedure or label, its size is defined by the amount of data
+ placed in the segment where the label is relative to. If a line of code
+ switches segments (for example in a macro) data placed in other segments
+ does not count for the size.
+
+ Please note that a symbol or scope must exist, before it is used together with
+ <tt/.SIZEOF/ (this may get relaxed later, but will always be true for scopes).
+ A scope has preference over a symbol with the same name, so if the last part
+ of a name represents both, a scope and a symbol, the scope is chosen over the
+ symbol.
+
+ After the following code:
+
+ <tscreen><verb>
+ .struct Point ; Struct size = 4
+ xcoord .word
+ ycoord .word
+ .endstruct
+
+ P: .tag Point ; Declare a point
+ @P: .tag Point ; Declare another point
+
+ .code
+ .proc Code
+ nop
+ .proc Inner
+ nop
+ .endproc
+ nop
+ .endproc
+
+ .proc Data
+ .data ; Segment switch!!!
+ .res 4
+ .endproc
+ </verb></tscreen>
+
+ <descrip>
+ <tag><tt/.sizeof(Point)/</tag>
+ will have the value 4, because this is the size of struct <tt/Point/.
+
+ <tag><tt/.sizeof(Point::xcoord)/</tag>
+ will have the value 2, because this is the size of the member <tt/xcoord/
+ in struct <tt/Point/.
+
+ <tag><tt/.sizeof(P)/</tag>
+ will have the value 4, this is the size of the data declared on the same
+ source line as the label <tt/P/, which is in the same segment that <tt/P/
+ is relative to.
+
+ <tag><tt/.sizeof(@P)/</tag>
+ will have the value 4, see above. The example demonstrates that <tt/.SIZEOF/
+ does also work for cheap local symbols.
+
+ <tag><tt/.sizeof(Code)/</tag>
+ will have the value 3, since this is amount of data emitted into the code
+ segment, the segment that was active when <tt/Code/ was entered. Note that
+ this value includes the amount of data emitted in child scopes (in this
+ case <tt/Code::Inner/).
+
+ <tag><tt/.sizeof(Code::Inner)/</tag>
+ will have the value 1 as expected.
+
+ <tag><tt/.sizeof(Data)/</tag>
+ will have the value 0. Data is emitted within the scope <tt/Data/, but since
+ the segment is switched after entry, this data is emitted into another
+ segment.
+ </descrip>
+
+
+<sect1><tt>.STRAT</tt><label id=".STRAT"><p>
+
+ Builtin function. The function accepts a string and an index as
+ arguments and returns the value of the character at the given position
+ as an integer value. The index is zero based.
+
+ Example:
+
+ <tscreen><verb>
+ .macro M Arg
+ ; Check if the argument string starts with '#'
+ .if (.strat (Arg, 0) = '#')
+ ...
+ .endif
+ .endmacro
+ </verb></tscreen>
+
+
+<sect1><tt>.SPRINTF</tt><label id=".SPRINTF"><p>
+
+ Builtin function. It expects a format string as first argument. The number
+ and type of the following arguments depend on the format string. The format
+ string is similar to the one of the C <tt/printf/ function. Missing things
+ are: Length modifiers, variable width.
+
+ The result of the function is a string.
+
+ Example:
+
+ <tscreen><verb>
+ num = 3
+
+ ; Generate an identifier:
+ .ident (.sprintf ("%s%03d", "label", num)):
+ </verb></tscreen>
+
+
+<sect1><tt>.STRING</tt><label id=".STRING"><p>
+
+ Builtin function. The function accepts an argument in braces and converts
+ this argument into a string constant. The argument may be an identifier, or
+ a constant numeric value.
+
+ Since you can use a string in the first place, the use of the function may
+ not be obvious. However, it is useful in macros, or more complex setups.
+
+ Example:
+
+ <tscreen><verb>
+ ; Emulate other assemblers:
+ .macro section name
+ .segment .string(name)
+ .endmacro
+ </verb></tscreen>
+
+
+<sect1><tt>.STRLEN</tt><label id=".STRLEN"><p>
+
+ Builtin function. The function accepts a string argument in braces and
+ evaluates to the length of the string.
-You may use cheap local labels as an easy way to reuse common label
-names like "Loop". Here is an example:
+ Example:
-<tscreen><verb>
- Clear: lda #$00 ; Global label
- ldy #$20
- @Loop: sta Mem,y ; Local label
- dey
- bne @Loop ; Ok
- rts
- Sub: ... ; New global label
- bne @Loop ; ERROR: Unknown identifier!
-</verb></tscreen>
+ The following macro encodes a string as a pascal style string with
+ a leading length byte.
-<sect1>Unnamed labels<p>
+ <tscreen><verb>
+ .macro PString Arg
+ .byte .strlen(Arg), Arg
+ .endmacro
+ </verb></tscreen>
-If you really want to write messy code, there are also unnamed
-labels. These labels do not have a name (you guessed that already,
-didn't you?). A colon is used to mark the absence of the name.
-Unnamed labels may be accessed by using the colon plus several minus
-or plus characters as a label designator. Using the '-' characters
-will create a back reference (use the n'th label backwards), using
-'+' will create a forward reference (use the n'th label in forward
-direction). An example will help to understand this:
+<sect1><tt>.TCOUNT</tt><label id=".TCOUNT"><p>
-<tscreen><verb>
- : lda (ptr1),y ; #1
- cmp (ptr2),y
- bne :+ ; -> #2
- tax
- beq :+++ ; -> #4
- iny
- bne :- ; -> #1
- inc ptr1+1
- inc ptr2+1
- bne :- ; -> #1
+ Builtin function. The function accepts a token list in braces. The function
+ result is the number of tokens given as argument. The token list may
+ optionally be enclosed into curly braces which are not considered part of
+ the list and not counted. Enclosement in curly braces allows the inclusion
+ of tokens that would otherwise terminate the list (the closing right paren
+ in the given case).
- : bcs :+ ; #2 -> #3
- ldx #$FF
- rts
+ Example:
- : ldx #$01 ; #3
- : rts ; #4
-</verb></tscreen>
+ The <tt/ldax/ macro accepts the '#' token to denote immediate addressing (as
+ with the normal 6502 instructions). To translate it into two separate 8 bit
+ load instructions, the '#' token has to get stripped from the argument:
-As you can see from the example, unnamed labels will make even short
-sections of code hard to understand, because you have to count labels
-to find branch targets (this is the reason why I for my part do
-prefer the "cheap" local labels). Nevertheless, unnamed labels are
-convenient in some situations, so it's your decision.
+ <tscreen><verb>
+ .macro ldax arg
+ .if (.match (.mid (0, 1, {arg}), #))
+ ; ldax called with immediate operand
+ lda #<(.right (.tcount ({arg})-1, {arg}))
+ ldx #>(.right (.tcount ({arg})-1, {arg}))
+ .else
+ ...
+ .endif
+ .endmacro
+ </verb></tscreen>
-<sect1>
Using macros to define labels and constants<p>
+<sect1>
<tt>.XMATCH</tt><label id=".XMATCH"><p>
-While there are drawbacks with this approach, it may be handy in some
-situations. Using <tt><ref id=".DEFINE" name=".DEFINE"></tt>, it is
-possible to define symbols or constants that may be used elsewhere. Since
-the macro facility works on a very low level, there is no scoping. On the
-other side, you may also define string constants this way (this is not
-possible with the other symbol types).
+ Builtin function. Matches two token lists against each other. This is
+ most useful within macros, since macros are not stored as strings, but
+ as lists of tokens.
-Example:
+ The syntax is
-<tscreen><verb>
- .DEFINE two 2
- .DEFINE version "SOS V2.3"
+ <tscreen><verb>
+ .XMATCH(<token list #1>, <token list #2>)
+ </verb></tscreen>
- four = two * two ; Ok
- .byte version ; Ok
+ Both token list may contain arbitrary tokens with the exception of the
+ terminator token (comma resp. right parenthesis) and
- .PROC ; Start local scope
- two = 3 ; Will give "2 = 3" - invalid!
- .ENDPROC
-</verb></tscreen>
+ <itemize>
+ <item>end-of-line
+ <item>end-of-file
+ </itemize>
+ The token lists may optionally be enclosed into curly braces. This allows
+ the inclusion of tokens that would otherwise terminate the list (the closing
+ right paren in the given case). Often a macro parameter is used for any of
+ the token lists.
-<sect1>Symbols and <tt>.DEBUGINFO</tt><p>
+ The function compares tokens <em/and/ token values. If you need a function
+ that just compares the type of tokens, have a look at the <tt><ref
+ id=".MATCH" name=".MATCH"></tt> function.
-If <tt><ref id=".DEBUGINFO" name=".DEBUGINFO"></tt> is enabled (or <ref
-id="option-g" name="-g"> is given on the command line), global, local and
-cheap local labels are written to the object file and will be available in the
-symbol file via the linker. Unnamed labels are not written to the object file,
-because they don't have a name which would allow to access them.
+ See: <tt><ref id=".MATCH" name=".MATCH"></tt>
-<sect>Control commands<label id="control-commands">
+<sect>Control commands<label id="control-commands"><p>
-<p>
Here's a list of all control commands and a description, what they do:
Valid only in 65816 mode. Switch the accumulator to 16 bit.
Note: This command will not emit any code, it will tell the assembler to
- create 16 bit operands for immediate accumulator adressing mode.
+ create 16 bit operands for immediate accumulator addressing mode.
See also: <tt><ref id=".SMART" name=".SMART"></tt>
Valid only in 65816 mode. Switch the accumulator to 8 bit.
Note: This command will not emit any code, it will tell the assembler to
- create 8 bit operands for immediate accu adressing mode.
+ create 8 bit operands for immediate accu addressing mode.
See also: <tt><ref id=".SMART" name=".SMART"></tt>
<sect1><tt>.ALIGN</tt><label id=".ALIGN"><p>
Align data to a given boundary. The command expects a constant integer
- argument that must be a power of two, plus an optional second argument
+ argument in the range 1 ... 65536, plus an optional second argument
in byte range. If there is a second argument, it is used as fill value,
otherwise the value defined in the linker configuration file is used
(the default for this value is zero).
- Since alignment depends on the base address of the module, you must
- give the same (or a greater) alignment for the segment when linking.
- The linker will give you a warning, if you don't do that.
+ <tt/.ALIGN/ will insert fill bytes, and the number of fill bytes depend of
+ the final address of the segment. <tt/.ALIGN/ cannot insert a variable
+ number of bytes, since that would break address calculations within the
+ module. So each <tt/.ALIGN/ expects the segment to be aligned to a multiple
+ of the alignment, because that allows the number of fill bytes to be
+ calculated in advance by the assembler. You are therefore required to
+ specify a matching alignment for the segment in the linker config. The
+ linker will output a warning if the alignment of the segment is less than
+ what is necessary to have a correct alignment in the object file.
Example:
.align 256
</verb></tscreen>
+ Some unexpected behaviour might occur if there are multiple <tt/.ALIGN/
+ commands with different arguments. To allow the assembler to calculate the
+ number of fill bytes in advance, the alignment of the segment must be a
+ multiple of each of the alignment factors. This may result in unexpectedly
+ large alignments for the segment within the module.
+
+ Example:
+
+ <tscreen><verb>
+ .align 15
+ .byte 15
+ .align 18
+ .byte 18
+ </verb></tscreen>
+
+ For the assembler to be able to align correctly, the segment must be aligned
+ to the least common multiple of 15 and 18 which is 90. The assembler will
+ calculate this automatically and will mark the segment with this value.
+
+ Unfortunately, the combined alignment may get rather large without the user
+ knowing about it, wasting space in the final executable. If we add another
+ alignment to the example above
+
+ <tscreen><verb>
+ .align 15
+ .byte 15
+ .align 18
+ .byte 18
+ .align 251
+ .byte 0
+ </verb></tscreen>
+
+ the assembler will force a segment alignment to the least common multiple of
+ 15, 18 and 251 - which is 22590. To protect the user against errors, the
+ assembler will issue a warning when the combined alignment exceeds 256. The
+ command line option <tt><ref id="option--large-alignment"
+ name="--large-alignment"></tt> will disable this warning.
+
+ Please note that with alignments that are a power of two (which were the
+ only alignments possible in older versions of the assembler), the problem is
+ less severe, because the least common multiple of powers to the same base is
+ always the larger one.
+
+
<sect1><tt>.ASCIIZ</tt><label id=".ASCIIZ"><p>
<sect1><tt>.ASSERT</tt><label id=".ASSERT"><p>
Add an assertion. The command is followed by an expression, an action
- specifier and a message that is output in case the assertion fails. The
- action specifier may be one of <tt/warning/ or <tt/error/. The assertion
- is passed to the linker and will be evaluated when segment placement has
- been done.
+ specifier, and an optional message that is output in case the assertion
+ fails. If no message was given, the string "Assertion failed" is used. The
+ action specifier may be one of <tt/warning/, <tt/error/, <tt/ldwarning/ or
+ <tt/lderror/. In the former two cases, the assertion is evaluated by the
+ assembler if possible, and in any case, it's also passed to the linker in
+ the object file (if one is generated). The linker will then evaluate the
+ expression when segment placement has been done.
Example:
when the output file is written, and abort with an error if this is not
the case. More complex expressions are possible. The action specifier
<tt/warning/ outputs a warning, while the <tt/error/ specifier outputs
- an error message. In the latter case, generation if the output file is
- suppressed.
+ an error message. In the latter case, generation of the output file is
+ suppressed in both the assembler and linker.
<sect1><tt>.AUTOIMPORT</tt><label id=".AUTOIMPORT"><p>
giving errors. When switched off (which is the default so this does not
make much sense), this does not happen and an error message is
displayed. The state of the autoimport flag is evaluated when the
- complete source was translated, before outputing actual code, so it is
+ complete source was translated, before outputting actual code, so it is
<em/not/ possible to switch this feature on or off for separate sections
of code. The last setting is used for all symbols.
.autoimport + ; Switch on auto import
</verb></tscreen>
+<sect1><tt>.BANKBYTES</tt><label id=".BANKBYTES"><p>
-<sect1><tt>.BLANK</tt><label id=".BLANK"><p>
+ Define byte sized data by extracting only the bank byte (that is, bits 16-23) from
+ each expression. This is equivalent to <tt><ref id=".BYTE" name=".BYTE"></tt> with
+ the operator '^' prepended to each expression in its list.
- Builtin function. The function evaluates its argument in braces and
- yields "false" if the argument is non blank (there is an argument), and
- "true" if there is no argument. As an example, the <tt/.IFBLANK/ statement
- may be replaced by
+ Example:
+
+ <tscreen><verb>
+ .define MyTable TableItem0, TableItem1, TableItem2, TableItem3
+
+ TableLookupLo: .lobytes MyTable
+ TableLookupHi: .hibytes MyTable
+ TableLookupBank: .bankbytes MyTable
+ </verb></tscreen>
+
+ which is equivalent to
<tscreen><verb>
- .if .blank(arg)
+ TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
+ TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
+ TableLookupBank: .byte ^TableItem0, ^TableItem1, ^TableItem2, ^TableItem3
</verb></tscreen>
+ See also: <tt><ref id=".BYTE" name=".BYTE"></tt>,
+ <tt><ref id=".HIBYTES" name=".HIBYTES"></tt>,
+ <tt><ref id=".LOBYTES" name=".LOBYTES"></tt>
+
<sect1><tt>.BSS</tt><label id=".BSS"><p>
<sect1><tt>.CHARMAP</tt><label id=".CHARMAP"><p>
Apply a custom mapping for characters. The command is followed by two
- numbers in the range 1..255. The first one is the index of the source
- character, the second one is the mapping. The mapping applies to all
- character and string constants when they generate output, and overrides
+ numbers. The first one is the index of the source character (range 0..255);
+ the second one is the mapping (range 0..255). The mapping applies to all
+ character and string constants <em/when/ they generate output; and, overrides
a mapping table specified with the <tt><ref id="option-t" name="-t"></tt>
command line switch.
Example:
-
<tscreen><verb>
- .charmap $41, $61 ; Map 'A' to 'a'
+ .charmap $41, $61 ; Map 'A' to 'a'
</verb></tscreen>
<tt/.CONDES/ is followed by the type, which may be <tt/constructor/,
<tt/destructor/ or a numeric value between 0 and 6 (where 0 is the same as
- specifiying <tt/constructor/ and 1 is equal to specifying <tt/destructor/).
- The <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
- id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> commands are actually shortcuts
- for <tt/.CONDES/ with a type of <tt/constructor/ resp. <tt/destructor/.
+ specifying <tt/constructor/ and 1 is equal to specifying <tt/destructor/).
+ The <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt>, <tt><ref
+ id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> and <tt><ref id=".INTERRUPTOR"
+ name=".INTERRUPTOR"></tt> commands are actually shortcuts for <tt/.CONDES/
+ with a type of <tt/constructor/ resp. <tt/destructor/ or <tt/interruptor/.
After the type, an optional priority may be specified. Higher numeric values
mean higher priority. If no priority is given, the default priority of 7 is
.condes ModInit, 0, 16
</verb></tscreen>
- See the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
- id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> commands and the separate section
- <ref id="condes" name="Module constructors/destructors"> explaining the
- feature in more detail.
-
-
-<sect1><tt>.CONCAT</tt><label id=".CONCAT"><p>
-
- Builtin function. The function allows to concatenate a list of string
- constants separated by commas. The result is a string constant that
- is the concatentation of all arguments. This function is most useful
- in macros and when used together with the <tt/.STRING/ builtin function.
- The function may be used in any case where a string constant is
- expected.
-
- Example:
-
- <tscreen><verb>
- .include .concat ("myheader", ".", "inc")
- </verb></tscreen>
-
- This is the same as the command
-
- <tscreen><verb>
- .include "myheader.inc"
- </verb></tscreen>
-
-
-<sect1><tt>.CONST</tt><label id=".CONST"><p>
-
- Builtin function. The function evaluates its argument in braces and
- yields "true" if the argument is a constant expression (that is, an
- expression that yields a constant value at assembly time) and "false"
- otherwise. As an example, the .IFCONST statement may be replaced by
-
- <tscreen><verb>
- .if .const(a + 3)
- </verb></tscreen>
+ See the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt>, <tt><ref
+ id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> and <tt><ref id=".INTERRUPTOR"
+ name=".INTERRUPTOR"></tt> commands and the separate section <ref id="condes"
+ name="Module constructors/destructors"> explaining the feature in more
+ detail.
<sect1><tt>.CONSTRUCTOR</tt><label id=".CONSTRUCTOR"><p>
feature in more detail.
-<sect1><tt>.CPU</tt><label id=".CPU"><p>
-
- Reading this pseudo variable will give a constant integer value that
- tells which CPU is currently enabled. It can also tell which instruction
- set the CPU is able to translate. The value read from the pseudo variable
- should be further examined by using one of the constants defined by the
- "cpu" macro package (see <tt/<ref id=".MACPACK" name=".MACPACK">/).
-
- It may be used to replace the .IFPxx pseudo instructions or to construct
- even more complex expressions.
-
- Example:
-
- <tscreen><verb>
- .macpack cpu
- .if (.cpu .bitand CPU_ISET_65816)
- phx
- phy
- .else
- txa
- pha
- tya
- pha
- .endif
- </verb></tscreen>
-
-
<sect1><tt>.DATA</tt><label id=".DATA"><p>
Switch to the DATA segment. The name of the DATA segment is always
Start a define style macro definition. The command is followed by an
identifier (the macro name) and optionally by a list of formal arguments
in braces.
- See section <ref id="macros" name="Macros">.
+
+ Please note that <tt/.DEFINE/ shares most disadvantages with its C
+ counterpart, so the general advice is, <bf/NOT/ do use <tt/.DEFINE/ if you
+ don't have to.
+
+ See also the <tt><ref id=".UNDEFINE" name=".UNDEFINE"></tt> command and
+ section <ref id="macros" name="Macros">.
+
+
+<sect1><tt>.DELMAC, .DELMACRO</tt><label id=".DELMACRO"><p>
+
+ Delete a classic macro (defined with <tt><ref id=".MACRO"
+ name=".MACRO"></tt>) . The command is followed by the name of an
+ existing macro. Its definition will be deleted together with the name.
+ If necessary, another macro with this name may be defined later.
+
+ See: <tt><ref id=".ENDMACRO" name=".ENDMACRO"></tt>,
+ <tt><ref id=".EXITMACRO" name=".EXITMACRO"></tt>,
+ <tt><ref id=".MACRO" name=".MACRO"></tt>
+
+ See also section <ref id="macros" name="Macros">.
<sect1><tt>.DEF, .DEFINED</tt><label id=".DEFINED"><p>
<tt><ref id=".IFDEF" name=".IFDEF"></tt> statement may be replaced by
<tscreen><verb>
- .if .defined(a)
+ .if .defined(a)
+ </verb></tscreen>
+
+
+<sect1><tt>.DEFINEDMACRO</tt><label id=".DEFINEDMACRO"><p>
+
+ Builtin function. The function expects an identifier as argument in braces.
+ The argument is evaluated, and the function yields "true" if the identifier
+ has already been defined as the name of a macro. Otherwise the function yields
+ false. Example:
+
+ <tscreen><verb>
+ .macro add foo
+ clc
+ adc foo
+ .endmacro
+
+ .if .definedmacro(add)
+ add #$01
+ .else
+ clc
+ adc #$01
+ .endif
</verb></tscreen>
is read from an include file.
+<sect1><tt>.ENDENUM</tt><label id=".ENDENUM"><p>
+
+ End a <tt><ref id=".ENUM" name=".ENUM"></tt> declaration.
+
+
<sect1><tt>.ENDIF</tt><label id=".ENDIF"><p>
Conditional assembly: Close a <tt><ref id=".IF" name=".IF..."></tt> or
<sect1><tt>.ENDMAC, .ENDMACRO</tt><label id=".ENDMACRO"><p>
- End of macro definition (see section <ref id="macros" name="Macros">).
+ Marks the end of a macro definition.
+
+ See: <tt><ref id=".DELMACRO" name=".DELMACRO"></tt>,
+ <tt><ref id=".EXITMACRO" name=".EXITMACRO"></tt>,
+ <tt><ref id=".MACRO" name=".MACRO"></tt>
+
+ See also section <ref id="macros" name="Macros">.
<sect1><tt>.ENDPROC</tt><label id=".ENDPROC"><p>
End a <tt><ref id=".REPEAT" name=".REPEAT"></tt> block.
+<sect1><tt>.ENDSCOPE</tt><label id=".ENDSCOPE"><p>
+
+ End of local lexical level (see <tt/<ref id=".SCOPE" name=".SCOPE">/).
+
+
+<sect1><tt>.ENDSTRUCT</tt><label id=".ENDSTRUCT"><p>
+
+ Ends a struct definition. See the <tt/<ref id=".STRUCT" name=".STRUCT">/
+ command and the separate section named <ref id="structs" name=""Structs
+ and unions"">.
+
+
+<sect1><tt>.ENDUNION</tt><label id=".ENDUNION"><p>
+
+ Ends a union definition. See the <tt/<ref id=".UNION" name=".UNION">/
+ command and the separate section named <ref id="structs" name=""Structs
+ and unions"">.
+
+
+<sect1><tt>.ENUM</tt><label id=".ENUM"><p>
+
+ Start an enumeration. This directive is very similar to the C <tt/enum/
+ keyword. If a name is given, a new scope is created for the enumeration,
+ otherwise the enumeration members are placed in the enclosing scope.
+
+ In the enumeration body, symbols are declared. The first symbol has a value
+ of zero, and each following symbol will get the value of the preceding plus
+ one. This behaviour may be overridden by an explicit assignment. Two symbols
+ may have the same value.
+
+ Example:
+
+ <tscreen><verb>
+ .enum errorcodes
+ no_error
+ file_error
+ parse_error
+ .endenum
+ </verb></tscreen>
+
+ Above example will create a new scope named <tt/errorcodes/ with three
+ symbols in it that get the values 0, 1 and 2 respectively. Another way
+ to write this would have been:
+
+ <tscreen><verb>
+ .scope errorcodes
+ no_error = 0
+ file_error = 1
+ parse_error = 2
+ .endscope
+ </verb></tscreen>
+
+ Please note that explicit scoping must be used to access the identifiers:
+
+ <tscreen><verb>
+ .word errorcodes::no_error
+ </verb></tscreen>
+
+ A more complex example:
+
+ <tscreen><verb>
+ .enum
+ EUNKNOWN = -1
+ EOK
+ EFILE
+ EBUSY
+ EAGAIN
+ EWOULDBLOCK = EAGAIN
+ .endenum
+ </verb></tscreen>
+
+ In this example, the enumeration does not have a name, which means that the
+ members will be visible in the enclosing scope and can be used in this scope
+ without explicit scoping. The first member (<tt/EUNKNOWN/) has the value -1.
+ The value for the following members is incremented by one, so <tt/EOK/ would
+ be zero and so on. <tt/EWOULDBLOCK/ is an alias for <tt/EGAIN/, so it has an
+ override for the value using an already defined symbol.
+
+
<sect1><tt>.ERROR</tt><label id=".ERROR"><p>
Force an assembly error. The assembler will output an error message
- preceeded by "User error" and will <em/not/ produce an object file.
+ preceded by "User error". Assembly is continued but no object file will
+ generated.
This command may be used to check for initial conditions that must be
set before assembling a source file.
.endif
</verb></tscreen>
- See also the <tt><ref id=".WARNING" name=".WARNING"></tt> and <tt><ref
- id=".OUT" name=".OUT"></tt> directives.
+ See also: <tt><ref id=".FATAL" name=".FATAL"></tt>,
+ <tt><ref id=".OUT" name=".OUT"></tt>,
+ <tt><ref id=".WARNING" name=".WARNING"></tt>
<sect1><tt>.EXITMAC, .EXITMACRO</tt><label id=".EXITMACRO"><p>
- Abort a macro expansion immidiately. This command is often useful in
- recursive macros. See separate section <ref id="macros" name="Macros">.
+ Abort a macro expansion immediately. This command is often useful in
+ recursive macros.
+
+ See: <tt><ref id=".DELMACRO" name=".DELMACRO"></tt>,
+ <tt><ref id=".ENDMACRO" name=".ENDMACRO"></tt>,
+ <tt><ref id=".MACRO" name=".MACRO"></tt>
+
+ See also section <ref id="macros" name="Macros">.
<sect1><tt>.EXPORT</tt><label id=".EXPORT"><p>
Make symbols accessible from other modules. Must be followed by a comma
- separated list of symbols to export.
+ separated list of symbols to export, with each one optionally followed by an
+ address specification and (also optional) an assignment. Using an additional
+ assignment in the export statement allows to define and export a symbol in
+ one statement. The default is to export the symbol with the address size it
+ actually has. The assembler will issue a warning, if the symbol is exported
+ with an address size smaller than the actual address size.
- Example:
+ Examples:
<tscreen><verb>
- .export foo, bar
+ .export foo
+ .export bar: far
+ .export foobar: far = foo * bar
+ .export baz := foobar, zap: far = baz - bar
</verb></tscreen>
+ As with constant definitions, using <tt/:=/ instead of <tt/=/ marks the
+ symbols as a label.
+
See: <tt><ref id=".EXPORTZP" name=".EXPORTZP"></tt>
Make symbols accessible from other modules. Must be followed by a comma
separated list of symbols to export. The exported symbols are explicitly
- marked as zero page symols.
+ marked as zero page symbols. An assignment may be included in the
+ <tt/.EXPORTZP/ statement. This allows to define and export a symbol in one
+ statement.
- Example:
+ Examples:
<tscreen><verb>
.exportzp foo, bar
+ .exportzp baz := $02
</verb></tscreen>
See: <tt><ref id=".EXPORT" name=".EXPORT"></tt>
See: <tt><ref id=".ADDR" name=".ADDR"></tt>
+<sect1><tt>.FATAL</tt><label id=".FATAL"><p>
+
+ Force an assembly error and terminate assembly. The assembler will output an
+ error message preceded by "User error" and will terminate assembly
+ immediately.
+
+ This command may be used to check for initial conditions that must be
+ set before assembling a source file.
+
+ Example:
+
+ <tscreen><verb>
+ .if foo = 1
+ ...
+ .elseif bar = 1
+ ...
+ .else
+ .fatal "Must define foo or bar!"
+ .endif
+ </verb></tscreen>
+
+ See also: <tt><ref id=".ERROR" name=".ERROR"></tt>,
+ <tt><ref id=".OUT" name=".OUT"></tt>,
+ <tt><ref id=".WARNING" name=".WARNING"></tt>
+
+
<sect1><tt>.FEATURE</tt><label id=".FEATURE"><p>
This directive may be used to enable one or more compatibility features
<descrip>
- <tag><tt>dollar_is_pc</tt></tag>
+ <tag><tt>addrsize</tt><label id="addrsize"></tag>
+
+ Enables the .ADDRSIZE pseudo function. This function is experimental and not enabled by default.
+
+ See also: <tt><ref id=".ADDRSIZE" name=".ADDRSIZE"></tt>
+
+ <tag><tt>at_in_identifiers</tt><label id="at_in_identifiers"></tag>
+
+ Accept the at character ('@') as a valid character in identifiers. The
+ at character is not allowed to start an identifier, even with this
+ feature enabled.
+
+ <tag><tt>bracket_as_indirect</tt><label id="bracket_as_indirect"></tag>
+
+ Use <tt>[]</tt> instead of <tt>()</tt> for the indirect addressing modes.
+ Example:
+
+ <tscreen><verb>
+ lda [$82]
+ lda [$82,x]
+ lda [$82],y
+ jmp [$fffe]
+ jmp [table,x]
+ </verb></tscreen>
+ <em/Note:/ This should not be used in 65186 mode because it conflicts with
+ the 65816 instruction syntax for far addressing. See the section covering
+ <tt/<ref id="address-sizes" name="address sizes">/ for more information.
+
+ <tag><tt>c_comments</tt><label id="c_comments"></tag>
+
+ Allow C like comments using <tt>/*</tt> and <tt>*/</tt> as left and right
+ comment terminators. Note that C comments may not be nested. There's also a
+ pitfall when using C like comments: All statements must be terminated by
+ "end-of-line". Using C like comments, it is possible to hide the newline,
+ which results in error messages. See the following non working example:
+
+ <tscreen><verb>
+ lda #$00 /* This comment hides the newline
+*/ sta $82
+ </verb></tscreen>
+
+ <tag><tt>dollar_in_identifiers</tt><label id="dollar_in_identifiers"></tag>
+
+ Accept the dollar sign ('$') as a valid character in identifiers. The
+ dollar character is not allowed to start an identifier, even with this
+ feature enabled.
- The dollar sign may be used as an alias for the star (`*'), which
+ <tag><tt>dollar_is_pc</tt><label id="dollar_is_pc"></tag>
+
+ The dollar sign may be used as an alias for the star ('*'), which
gives the value of the current PC in expressions.
Note: Assignment to the pseudo variable is not allowed.
- <tag><tt>labels_without_colons</tt></tag>
+ <tag><tt>force_range</tt><label id="force_range"></tag>
+
+ Force expressions into their valid range for immediate addressing and
+ storage operators like <tt><ref id=".BYTE" name=".BYTE"></tt> and
+ <tt><ref id=".WORD" name=".WORD"></tt>. Be very careful with this one,
+ since it will completely disable error checks.
+
+ <tag><tt>labels_without_colons</tt><label id="labels_without_colons"></tag>
Allow labels without a trailing colon. These labels are only accepted,
if they start at the beginning of a line (no leading white space).
- <tag><tt>loose_string_term</tt></tag>
+ <tag><tt>leading_dot_in_identifiers</tt><label id="leading_dot_in_identifiers"></tag>
- Accept single quotes as well as double quotes as terminators for string
- constants.
+ Accept the dot ('.') as the first character of an identifier. This may be
+ used for example to create macro names that start with a dot emulating
+ control directives of other assemblers. Note however, that none of the
+ reserved keywords built into the assembler, that starts with a dot, may be
+ overridden. When using this feature, you may also get into trouble if
+ later versions of the assembler define new keywords starting with a dot.
- <tag><tt>loose_char_term</tt></tag>
+ <tag><tt>loose_char_term</tt><label id="loose_char_term"></tag>
Accept single quotes as well as double quotes as terminators for char
constants.
- <tag><tt>at_in_identifiers</tt></tag>
+ <tag><tt>loose_string_term</tt><label id="loose_string_term"></tag>
- Accept the at character (`@') as a valid character in identifiers. The
- at character is not allowed to start an identifier, even with this
- feature enabled.
+ Accept single quotes as well as double quotes as terminators for string
+ constants.
- <tag><tt>dollar_in_identifiers</tt></tag>
+ <tag><tt>missing_char_term</tt><label id="missing_char_term"></tag>
- Accept the dollar sign (`$') as a valid character in identifiers. The
- at character is not allowed to start an identifier, even with this
- feature enabled.
+ Accept single quoted character constants where the terminating quote is
+ missing.
+ <tscreen><verb>
+ lda #'a
+ </verb></tscreen>
+ <em/Note:/ This does not work in conjunction with <tt/.FEATURE
+ loose_string_term/, since in this case the input would be ambiguous.
- <tag><tt>leading_dot_in_identifiers</tt></tag>
+ <tag><tt>org_per_seg</tt><label id="org_per_seg"></tag>
- Accept the dot (`.') as the first character of an identifier. This may be
- used for example to create macro names that start with a dot emulating
- control directives of other assemblers. Note however, that none of the
- reserved keywords built into the assembler, that starts with a dot, may be
- overridden. When using this feature, you may also get into trouble if
- later versions of the assembler define new keywords starting with a dot.
+ This feature makes relocatable/absolute mode local to the current segment.
+ Using <tt><ref id=".ORG" name=".ORG"></tt> when <tt/org_per_seg/ is in
+ effect will only enable absolute mode for the current segment. Dito for
+ <tt><ref id=".RELOC" name=".RELOC"></tt>.
- <tag><tt>pc_assignment</tt></tag>
+ <tag><tt>pc_assignment</tt><label id="pc_assignment"></tag>
- Allow assignments to the PC symbol (`*' or `$' if <tt/dollar_is_pc/
+ Allow assignments to the PC symbol ('*' or '$' if <tt/dollar_is_pc/
is enabled). Such an assignment is handled identical to the <tt><ref
id=".ORG" name=".ORG"></tt> command (which is usually not needed, so just
removing the lines with the assignments may also be an option when porting
code written for older assemblers).
+ <tag><tt>ubiquitous_idents</tt><label id="ubiquitous_idents"></tag>
+
+ Allow the use of instructions names as names for macros and symbols. This
+ makes it possible to "overload" instructions by defining a macro with the
+ same name. This does also make it possible to introduce hard to find errors
+ in your code, so be careful!
+
+ <tag><tt>underline_in_numbers</tt><label id="underline_in_numbers"></tag>
+
+ Allow underlines within numeric constants. These may be used for grouping
+ the digits of numbers for easier reading.
+ Example:
+ <tscreen><verb>
+ .feature underline_in_numbers
+ .word %1100001110100101
+ .word %1100_0011_1010_0101 ; Identical but easier to read
+ </verb></tscreen>
+
</descrip>
It is also possible to specify features on the command line using the
source, are exported, all others are imported. Additional <tt><ref
id=".IMPORTZP" name=".IMPORTZP"></tt> or <tt><ref id=".EXPORTZP"
name=".EXPORTZP"></tt> commands for the same symbol are allowed. The symbols
- in the list are explicitly marked as zero page symols.
+ in the list are explicitly marked as zero page symbols.
Example:
.globalzp foo, bar
</verb></tscreen>
+<sect1><tt>.HIBYTES</tt><label id=".HIBYTES"><p>
+
+ Define byte sized data by extracting only the high byte (that is, bits 8-15) from
+ each expression. This is equivalent to <tt><ref id=".BYTE" name=".BYTE"></tt> with
+ the operator '>' prepended to each expression in its list.
+
+ Example:
+
+ <tscreen><verb>
+ .lobytes $1234, $2345, $3456, $4567
+ .hibytes $fedc, $edcb, $dcba, $cba9
+ </verb></tscreen>
+
+ which is equivalent to
+
+ <tscreen><verb>
+ .byte $34, $45, $56, $67
+ .byte $fe, $ed, $dc, $cb
+ </verb></tscreen>
+
+ Example:
+
+ <tscreen><verb>
+ .define MyTable TableItem0, TableItem1, TableItem2, TableItem3
+
+ TableLookupLo: .lobytes MyTable
+ TableLookupHi: .hibytes MyTable
+ </verb></tscreen>
+
+ which is equivalent to
+
+ <tscreen><verb>
+ TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
+ TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
+ </verb></tscreen>
+
+ See also: <tt><ref id=".BYTE" name=".BYTE"></tt>,
+ <tt><ref id=".LOBYTES" name=".LOBYTES"></tt>,
+ <tt><ref id=".BANKBYTES" name=".BANKBYTES"></tt>
+
<sect1><tt>.I16</tt><label id=".I16"><p>
<sect1><tt>.IF</tt><label id=".IF"><p>
- Conditional assembly: Evalute an expression and switch assembler output
+ Conditional assembly: Evaluate an expression and switch assembler output
on or off depending on the expression. The expression must be a constant
expression, that is, all operands must be defined.
Conditional assembly: Check if there are any remaining tokens in this line,
and evaluate to FALSE if this is the case, and to TRUE otherwise. If the
condition is not true, further lines are not assembled until an <tt><ref
- id=".ELSE" name=".ESLE"></tt>, <tt><ref id=".ELSEIF" name=".ELSEIF"></tt> or
+ id=".ELSE" name=".ELSE"></tt>, <tt><ref id=".ELSEIF" name=".ELSEIF"></tt> or
<tt><ref id=".ENDIF" name=".ENDIF"></tt> directive.
This command is often used to check if a macro parameter was given. Since an
empty macro parameter will evaluate to nothing, the condition will evaluate
- to FALSE if an empty parameter was given.
+ to TRUE if an empty parameter was given.
Example:
(see <tt><ref id=".P02" name=".P02"></tt> command).
+<sect1><tt>.IFP4510</tt><label id=".IFP4510"><p>
+
+ Conditional assembly: Check if the assembler is currently in 4510 mode
+ (see <tt><ref id=".P4510" name=".P4510"></tt> command).
+
+
<sect1><tt>.IFP816</tt><label id=".IFP816"><p>
Conditional assembly: Check if the assembler is currently in 65816 mode
<sect1><tt>.IMPORT</tt><label id=".IMPORT"><p>
Import a symbol from another module. The command is followed by a comma
- separated list of symbols to import.
+ separated list of symbols to import, with each one optionally followed by
+ an address specification.
Example:
<tscreen><verb>
- .import foo, bar
+ .import foo
+ .import bar: zeropage
</verb></tscreen>
See: <tt><ref id=".IMPORTZP" name=".IMPORTZP"></tt>
In addition to that, a start offset and a size value may be specified,
separated by commas. If no size is specified, all of the file from the
start offset to end-of-file is used. If no start position is specified
- either, zero is assume (which means that the whole file is inserted).
+ either, zero is assumed (which means that the whole file is inserted).
Example:
</verb></tscreen>
-<sect1><tt>.
LEFT</tt><label id=".LEFT"><p>
+<sect1><tt>.
INTERRUPTOR</tt><label id=".INTERRUPTOR"><p>
- Builtin function. Extracts the left part of a given token list.
+ Export a symbol and mark it as an interruptor. This may be used together
+ with the linker to build a table of interruptor subroutines that are called
+ in an interrupt.
- Syntax:
+ Note: The linker has a feature to build a table of marked routines, but it
+ is your code that must call these routines, so just declaring a symbol as
+ interruptor does nothing by itself.
+
+ An interruptor is always exported as an absolute (16 bit) symbol. You don't
+ need to use an additional <tt/.export/ statement, this is implied by
+ <tt/.interruptor/. It may have an optional priority that is separated by a
+ comma. Higher numeric values mean a higher priority. If no priority is
+ given, the default priority of 7 is used. Be careful when assigning
+ priorities to your own module constructors so they won't interfere with the
+ ones in the cc65 library.
+
+ Example:
<tscreen><verb>
- .LEFT (<int expr>, <token list>)
+ .interruptor IrqHandler
+ .interruptor Handler, 16
</verb></tscreen>
- The first integer expression gives the number of tokens to extract from
- the token list. The second argument is the token list itself.
-
- Example:
+ See the <tt><ref id=".CONDES" name=".CONDES"></tt> command and the separate
+ section <ref id="condes" name="Module constructors/destructors"> explaining
+ the feature in more detail.
- To check in a macro if the given argument has a '#' as first token
- (immidiate addressing mode), use something like this:
- <tscreen><verb>
- .macro ldax arg
- ...
- .if (.match (.left (1, arg), #))
+<sect1><tt>.ISMNEM, .ISMNEMONIC</tt><label id=".ISMNEMONIC"><p>
- ; ldax called with immidiate operand
- ...
+ Builtin function. The function expects an identifier as argument in braces.
+ The argument is evaluated, and the function yields "true" if the identifier
+ is defined as an instruction mnemonic that is recognized by the assembler.
+ Example:
- .endif
- ...
- .endmacro
+ <tscreen><verb>
+ .if .not .ismnemonic(ina)
+ .macro ina
+ clc
+ adc #$01
+ .endmacro
+ .endif
</verb></tscreen>
- See also the <tt><ref id=".MID" name=".MID"></tt> and <tt><ref id=".RIGHT"
- name=".RIGHT"></tt> builtin functions.
-
<sect1><tt>.LINECONT</tt><label id=".LINECONT"><p>
</verb></tscreen>
+<sect1><tt>.LOBYTES</tt><label id=".LOBYTES"><p>
+
+ Define byte sized data by extracting only the low byte (that is, bits 0-7) from
+ each expression. This is equivalent to <tt><ref id=".BYTE" name=".BYTE"></tt> with
+ the operator '<' prepended to each expression in its list.
+
+ Example:
+
+ <tscreen><verb>
+ .lobytes $1234, $2345, $3456, $4567
+ .hibytes $fedc, $edcb, $dcba, $cba9
+ </verb></tscreen>
+
+ which is equivalent to
+
+ <tscreen><verb>
+ .byte $34, $45, $56, $67
+ .byte $fe, $ed, $dc, $cb
+ </verb></tscreen>
+
+ Example:
+
+ <tscreen><verb>
+ .define MyTable TableItem0, TableItem1, TableItem2, TableItem3
+
+ TableLookupLo: .lobytes MyTable
+ TableLookupHi: .hibytes MyTable
+ </verb></tscreen>
+
+ which is equivalent to
+
+ <tscreen><verb>
+ TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
+ TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
+ </verb></tscreen>
+
+ See also: <tt><ref id=".BYTE" name=".BYTE"></tt>,
+ <tt><ref id=".HIBYTES" name=".HIBYTES"></tt>,
+ <tt><ref id=".BANKBYTES" name=".BANKBYTES"></tt>
+
+
<sect1><tt>.LOCAL</tt><label id=".LOCAL"><p>
This command may only be used inside a macro definition. It declares a
packages are:
<tscreen><verb>
- generic Defines generic macros like add and sub.
- longbranch Defines conditional long jump macros.
- cbm Defines the scrcode macro
- cpu Defines constants for the .CPU variable
+ atari Defines the scrcode macro.
+ cbm Defines the scrcode macro.
+ cpu Defines constants for the .CPU variable.
+ generic Defines generic macroes like add, sub, and blt.
+ longbranch Defines conditional long-jump macroes.
</verb></tscreen>
Including a macro package twice, or including a macro package that
<tscreen><verb>
.macpack longbranch ; Include macro package
- cmp #$20 ; Set condition codes
- jne Label ; Jump long on condition
+ cmp #$20 ; Set condition codes
+ jne Label ; Jump long on condition
</verb></tscreen>
Macro packages are explained in more detail in section <ref
id="macropackages" name="Macro packages">.
-<sect1><tt>.MAC, .MACRO</tt><label id=".MAC"><p>
+<sect1><tt>.MAC, .MACRO</tt><label id=".MAC
RO"><p>
Start a classic macro definition. The command is followed by an identifier
(the macro name) and optionally by a comma separated list of identifiers
- that are macro parameters.
-
- See section <ref id="macros" name="Macros">.
-
-
-<sect1><tt>.MATCH</tt><label id=".MATCH"><p>
-
- Builtin function. Matches two token lists against each other. This is
- most useful within macros, since macros are not stored as strings, but
- as lists of tokens.
-
- The syntax is
-
- <tscreen><verb>
- .MATCH(<token list #1>, <token list #2>)
- </verb></tscreen>
-
- Both token list may contain arbitrary tokens with the exception of the
- terminator token (comma resp. right parenthesis) and
-
- <itemize>
- <item>end-of-line
- <item>end-of-file
- </itemize>
-
- Often a macro parameter is used for any of the token lists.
-
- Please note that the function does only compare tokens, not token
- attributes. So any number is equal to any other number, regardless of the
- actual value. The same is true for strings. If you need to compare tokens
- <em/and/ token attributes, use the <tt><ref id=".XMATCH"
- name=".XMATCH"></tt> function.
+ that are macro parameters. A macro definition is terminated by <tt><ref
+ id=".ENDMACRO" name=".ENDMACRO"></tt>.
Example:
- Assume the macro <tt/ASR/, that will shift right the accumulator by one,
- while honoring the sign bit. The builtin processor instructions will allow
- an optional "A" for accu addressing for instructions like <tt/ROL/ and
- <tt/ROR/. We will use the <tt><ref id=".MATCH" name=".MATCH"></tt> function
- to check for this and print and error for invalid calls.
-
- <tscreen><verb>
- .macro asr arg
-
- .if (.not .blank(arg)) .and (.not .match (arg, a))
- .error "Syntax error"
- .endif
-
- cmp #$80 ; Bit 7 into carry
- lsr a ; Shift carry into bit 7
-
- .endmacro
- </verb></tscreen>
-
- The macro will only accept no arguments, or one argument that must be the
- reserved keyword "A".
-
- See: <tt><ref id=".XMATCH" name=".XMATCH"></tt>
-
-
-<sect1><tt>.MID</tt><label id=".MID"><p>
-
- Builtin function. Takes a starting index, a count and a token list as
- arguments. Will return part of the token list.
-
- Syntax:
-
<tscreen><verb>
- .MID (<int expr>, <int expr>, <token list>)
+ .macro ldax arg ; Define macro ldax
+ lda arg
+ ldx arg+1
</verb></tscreen>
- The first integer expression gives the starting token in the list (the
- first token has index 0). The second integer expression gives the number
- of tokens to extract from the token list. The third argument is the
- token list itself.
-
- Example:
-
- To check in a macro if the given argument has a '<tt/#/' as first token
- (immidiate addressing mode), use something like this:
-
- <tscreen><verb>
- .macro ldax arg
- ...
- .if (.match (.mid (0, 1, arg), #))
-
- ; ldax called with immidiate operand
- ...
-
- .endif
- ...
- .endmacro
- </verb></tscreen>
+ See: <tt><ref id=".DELMACRO" name=".DELMACRO"></tt>,
+ <tt><ref id=".ENDMACRO" name=".ENDMACRO"></tt>,
+ <tt><ref id=".EXITMACRO" name=".EXITMACRO"></tt>
- See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".RIGHT"
- name=".RIGHT"></tt> builtin functions.
+ See also section <ref id="macros" name="Macros">.
<sect1><tt>.ORG</tt><label id=".ORG"><p>
assembled. Use <tt><ref id=".RELOC" name=".RELOC"></tt> to switch back to
relocatable code.
- Please note that you <em/do not need/ this command in most cases. Placing
+ By default, absolute/relocatable mode is global (valid even when switching
+ segments). Using <tt>.FEATURE <ref id="org_per_seg" name="org_per_seg"></tt>
+ it can be made segment local.
+
+ Please note that you <em/do not need/ <tt/.ORG/ in most cases. Placing
code at a specific address is the job of the linker, not the assembler, so
there is usually no reason to assemble code to a specific address.
- You may not switch segments while inside a section of absolute code.
-
Example:
<tscreen><verb>
<sect1><tt>.OUT</tt><label id=".OUT"><p>
Output a string to the console without producing an error. This command
- is similiar to <tt/.ERROR/, however, it does not force an assembler error
+ is similar to <tt/.ERROR/, however, it does not force an assembler error
that prevents the creation of an object file.
Example:
.out "This code was written by the codebuster(tm)"
</verb></tscreen>
- See also the <tt><ref id=".WARNING" name=".WARNING"></tt> and <tt><ref
- id=".ERROR" name=".ERROR"></tt> directives.
+ See also: <tt><ref id=".ERROR" name=".ERROR"></tt>,
+ <tt><ref id=".FATAL" name=".FATAL"></tt>,
+ <tt><ref id=".WARNING" name=".WARNING"></tt>
<sect1><tt>.P02</tt><label id=".P02"><p>
<tt><ref id="option--cpu" name="--cpu"></tt> command line option.
See: <tt><ref id=".PC02" name=".PC02"></tt>, <tt><ref id=".PSC02"
- name=".PSC02"></tt> and <tt><ref id=".P816" name=".P816"></tt>
+ name=".PSC02"></tt>, <tt><ref id=".P816" name=".P816"></tt> and
+ <tt><ref id=".P4510" name=".P4510"></tt>
+
+
+<sect1><tt>.P4510</tt><label id=".P4510"><p>
+
+ Enable the 4510 instruction set. This is a superset of the 65C02 and
+ 6502 instruction sets.
+
+ See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PSC02"
+ name=".PSC02"></tt>, <tt><ref id=".PC02" name=".PC02"></tt> and
+ <tt><ref id=".P816" name=".P816"></tt>
<sect1><tt>.P816</tt><label id=".P816"><p>
6502 instruction sets.
See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PSC02"
- name=".PSC02"></tt> and <tt><ref id=".PC02" name=".PC02"></tt>
+ name=".PSC02"></tt>, <tt><ref id=".PC02" name=".PC02"></tt> and
+ <tt><ref id=".P4510" name=".P4510"></tt>
<sect1><tt>.PAGELEN, .PAGELENGTH</tt><label id=".PAGELENGTH"><p>
</verb></tscreen>
-<sect1><tt>.P
ARAMCOUNT</tt><label id=".PARAMCOUNT"><p>
+<sect1><tt>.P
C02</tt><label id=".PC02"><p>
- This builtin pseudo variable is only available in macros. It is replaced by
- the actual number of parameters that were given in the macro invocation.
+ Enable the 65C02 instructions set. This instruction set includes all
+ 6502 and 65SC02 instructions.
- Example:
+ See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PSC02"
+ name=".PSC02"></tt>, <tt><ref id=".P816" name=".P816"></tt> and
+ <tt><ref id=".P4510" name=".P4510"></tt>
- <tscreen><verb>
- .macro foo arg1, arg2, arg3
- .if .paramcount <> 3
- .error "Too few parameters for macro foo"
- .endif
- ...
- .endmacro
- </verb></tscreen>
- See section <ref id="macros" name="Macros">.
+<sect1><tt>.POPCPU</tt><label id=".POPCPU"><p>
+ Pop the last CPU setting from the stack, and activate it.
-<sect1><tt>.PC02</tt><label id=".PC02"><p>
+ This command will switch back to the CPU that was last pushed onto the CPU
+ stack using the <tt><ref id=".PUSHCPU" name=".PUSHCPU"></tt> command, and
+ remove this entry from the stack.
- Enable the 65C02 instructions set. This instruction set includes all
- 6502 and 65SC02 instructions.
+ The assembler will print an error message if the CPU stack is empty when
+ this command is issued.
- See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PSC02"
- name=".PSC02"></tt> and <tt><ref id=".P816" name=".P816"></tt>
+ See: <tt><ref id=".CPU" name=".CPU"></tt>, <tt><ref id=".PUSHCPU"
+ name=".PUSHCPU"></tt>, <tt><ref id=".SETCPU" name=".SETCPU"></tt>
<sect1><tt>.POPSEG</tt><label id=".POPSEG"><p>
<sect1><tt>.PROC</tt><label id=".PROC"><p>
- Start a nested lexical level. All new symbols from now on are in the local
- lexical level and are not accessible from outside. Symbols defined outside
- this local level may be accessed as long as their names are not used for new
- symbols inside the level. Symbols names in other lexical levels do not
- clash, so you may use the same names for identifiers. The lexical level ends
- when the <tt><ref id=".ENDPROC" name=".ENDPROC"></tt> command is read.
- Lexical levels may be nested up to a depth of 16.
-
- The command may be followed by an identifier, in this case the
- identifier is declared in the outer level as a label having the value of
- the program counter at the start of the lexical level.
+ Start a nested lexical level with the given name and adds a symbol with this
+ name to the enclosing scope. All new symbols from now on are in the local
+ lexical level and are accessible from outside only via <ref id="scopesyntax"
+ name="explicit scope specification">. Symbols defined outside this local
+ level may be accessed as long as their names are not used for new symbols
+ inside the level. Symbols names in other lexical levels do not clash, so you
+ may use the same names for identifiers. The lexical level ends when the
+ <tt><ref id=".ENDPROC" name=".ENDPROC"></tt> command is read. Lexical levels
+ may be nested up to a depth of 16 (this is an artificial limit to protect
+ against errors in the source).
Note: Macro names are always in the global level and in a separate name
space. There is no special reason for this, it's just that I've never
.endproc ; Leave lexical level
</verb></tscreen>
- See: <tt><ref id=".ENDPROC" name=".ENDPROC"></tt>
+ See: <tt/<ref id=".ENDPROC" name=".ENDPROC">/ and <tt/<ref id=".SCOPE"
+ name=".SCOPE">/
<sect1><tt>.PSC02</tt><label id=".PSC02"><p>
6502 instructions.
See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PC02"
- name=".PC02"></tt> and <tt><ref id=".P816" name=".P816"></tt>
+ name=".PC02"></tt>, <tt><ref id=".P816" name=".P816"></tt> and
+ <tt><ref id=".P4510" name=".P4510"></tt>
+
+
+<sect1><tt>.PUSHCPU</tt><label id=".PUSHCPU"><p>
+
+ Push the currently active CPU onto a stack. The stack has a size of 8
+ entries.
+
+ <tt/.PUSHCPU/ allows together with <tt><ref id=".POPCPU"
+ name=".POPCPU"></tt> to switch to another CPU and to restore the old CPU
+ later, without knowledge of the current CPU setting.
+
+ The assembler will print an error message if the CPU stack is already full,
+ when this command is issued.
+
+ See: <tt><ref id=".CPU" name=".CPU"></tt>, <tt><ref id=".POPCPU"
+ name=".POPCPU"></tt>, <tt><ref id=".SETCPU" name=".SETCPU"></tt>
<sect1><tt>.PUSHSEG</tt><label id=".PUSHSEG"><p>
See: <tt><ref id=".POPSEG" name=".POPSEG"></tt>
-<sect1><tt>.REF, .REFERENCED</tt><label id=".REFERENCED"><p>
-
- Builtin function. The function expects an identifier as argument in braces.
- The argument is evaluated, and the function yields "true" if the identifier
- is a symbol that has already been referenced somewhere in the source file up
- to the current position. Otherwise the function yields false. As an example,
- the <tt><ref id=".IFREF" name=".IFREF"></tt> statement may be replaced by
-
- <tscreen><verb>
- .if .referenced(a)
- </verb></tscreen>
+<sect1><tt>.RELOC</tt><label id=".RELOC"><p>
- See: <tt><ref id=".DEFINED" name=".DEFINED"></tt>
+ Switch back to relocatable mode. See the <tt><ref id=".ORG"
+ name=".ORG"></tt> command.
<sect1><tt>.REPEAT</tt><label id=".REPEAT"><p>
<tscreen><verb>
.macro Crypt Arg
.repeat .strlen(Arg), I
- .byte .strat(Arg, I) .xor $55
+ .byte .strat(Arg, I) ^ $55
.endrep
.endmacro
</verb></tscreen>
See: <tt><ref id=".ENDREPEAT" name=".ENDREPEAT"></tt>
-<sect1><tt>.RELOC</tt><label id=".RELOC"><p>
-
- Switch back to relocatable mode. See the <tt><ref id=".ORG"
- name=".ORG"></tt> command.
-
-
<sect1><tt>.RES</tt><label id=".RES"><p>
Reserve storage. The command is followed by one or two constant
is no fill value given, the linker will use the value defined in the
linker configuration file (default: zero).
- Example:
-
- <tscreen><verb>
- ; Reserve 12 bytes of memory with value $AA
- .res 12, $AA
- </verb></tscreen>
-
-
-<sect1><tt>.RIGHT</tt><label id=".RIGHT"><p>
-
- Builtin function. Extracts the right part of a given token list.
-
- Syntax:
-
- <tscreen><verb>
- .RIGHT (<int expr>, <token list>)
- </verb></tscreen>
-
- The first integer expression gives the number of tokens to extract from
- the token list. The second argument is the token list itself.
+ Example:
- See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".MID"
- name=".MID"></tt> builtin functions.
+ <tscreen><verb>
+ ; Reserve 12 bytes of memory with value $AA
+ .res 12, $AA
+ </verb></tscreen>
<sect1><tt>.RODATA</tt><label id=".RODATA"><p>
See also the <tt><ref id=".SEGMENT" name=".SEGMENT"></tt> command.
+<sect1><tt>.SCOPE</tt><label id=".SCOPE"><p>
+
+ Start a nested lexical level with the given name. All new symbols from now
+ on are in the local lexical level and are accessible from outside only via
+ <ref id="scopesyntax" name="explicit scope specification">. Symbols defined
+ outside this local level may be accessed as long as their names are not used
+ for new symbols inside the level. Symbols names in other lexical levels do
+ not clash, so you may use the same names for identifiers. The lexical level
+ ends when the <tt><ref id=".ENDSCOPE" name=".ENDSCOPE"></tt> command is
+ read. Lexical levels may be nested up to a depth of 16 (this is an
+ artificial limit to protect against errors in the source).
+
+ Note: Macro names are always in the global level and in a separate name
+ space. There is no special reason for this, it's just that I've never
+ had any need for local macro definitions.
+
+ Example:
+
+ <tscreen><verb>
+ .scope Error ; Start new scope named Error
+ None = 0 ; No error
+ File = 1 ; File error
+ Parse = 2 ; Parse error
+ .endscope ; Close lexical level
+
+ ...
+ lda #Error::File ; Use symbol from scope Error
+ </verb></tscreen>
+
+ See: <tt/<ref id=".ENDSCOPE" name=".ENDSCOPE">/ and <tt/<ref id=".PROC"
+ name=".PROC">/
+
+
<sect1><tt>.SEGMENT</tt><label id=".SEGMENT"><p>
Switch to another segment. Code and data is always emitted into a
segment, that is, a named section of data. The default segment is
"CODE". There may be up to 254 different segments per object file
(and up to 65534 per executable). There are shortcut commands for
- the most common segments ("CODE", "DATA" and "BSS").
+ the most common segments ("ZEROPAGE", "CODE", "RODATA", "DATA", and "BSS").
- The command is followed by a string containing the segment name (there
- are some constraints for the name - as a rule of thumb use only those
- segment names that would also be valid identifiers). There may also be
- an optional attribute separated by a comma. Valid attributes are
- "<tt/zeropage/" and "<tt/absolute/".
+ The command is followed by a string containing the segment name (there are
+ some constraints for the name - as a rule of thumb use only those segment
+ names that would also be valid identifiers). There may also be an optional
+ address size separated by a colon. See the section covering <tt/<ref
+ id="address-sizes" name="address sizes">/ for more information.
- When specifying a segment for the first time, "absolute" is the
- default. For all other uses, the attribute specified the first time
- is the default.
+ The default address size for a segment depends on the memory model specified
+ on the command line. The default is "absolute", which means that you don't
+ have to use an address size modifier in most cases.
- "absolute" means that this is a segment with absolute addressing. That
- is, the segment will reside somewhere in core memory outside the zero
- page. "zeropage" means the opposite: The segment will be placed in the
- zero page and direct (short) addressing is possible for data in this
- segment.
+ "absolute" means that the is a segment with 16 bit (absolute) addressing.
+ That is, the segment will reside somewhere in core memory outside the zero
+ page. "zeropage" (8 bit) means that the segment will be placed in the zero
+ page and direct (short) addressing is possible for data in this segment.
Beware: Only labels in a segment with the zeropage attribute are marked
- as reachable by short addressing. The `*' (PC counter) operator will
+ as reachable by short addressing. The '*' (PC counter) operator will
work as in other segments and will create absolute variable values.
- Example:
+ Please note that a segment cannot have two different address sizes. A
+ segment specified as zeropage cannot be declared as being absolute later.
+
+ Examples:
<tscreen><verb>
.segment "ROM2" ; Switch to ROM2 segment
- .segment "ZP2", zeropage ; New direct segment
- .segment "ZP2" ; Ok, will use last attribute
- .segment "ZP2", absolute ; Error, redecl mismatch
+ .segment "ZP2": zeropage ; New direct segment
+ .segment "ZP2" ; Ok, will use last attribute
+ .segment "ZP2": absolute ; Error, redecl mismatch
</verb></tscreen>
See: <tt><ref id=".BSS" name=".BSS"></tt>, <tt><ref id=".CODE"
- name=".CODE"></tt>, <tt><ref id=".DATA" name=".DATA"></tt> and <tt><ref
- id=".RODATA" name=".RODATA"></tt>
+ name=".CODE"></tt>, <tt><ref id=".DATA" name=".DATA"></tt>, <tt><ref
+ id=".RODATA" name=".RODATA"></tt>, and <tt><ref id=".ZEROPAGE"
+ name=".ZEROPAGE"></tt>
+
+
+<sect1><tt>.SET</tt><label id=".SET"><p>
+
+ <tt/.SET/ is used to assign a value to a variable. See <ref id="variables"
+ name="Numeric variables"> for a full description.
<sect1><tt>.SETCPU</tt><label id=".SETCPU"><p>
Switch the CPU instruction set. The command is followed by a string that
specifies the CPU. Possible values are those that can also be supplied to
the <tt><ref id="option--cpu" name="--cpu"></tt> command line option,
- namely: 6502, 65SC02, 65C02, 65816 and sunplus. Please note that support
- for the sunplus CPU is not available in the freeware version, because the
- instruction set of the sunplus CPU is "proprietary and confidential".
+ namely: 6502, 6502X, 65SC02, 65C02, 65816, 4510 and HuC6280.
See: <tt><ref id=".CPU" name=".CPU"></tt>,
<tt><ref id=".IFP02" name=".IFP02"></tt>,
<tt><ref id=".IFPSC02" name=".IFPSC02"></tt>,
<tt><ref id=".P02" name=".P02"></tt>,
<tt><ref id=".P816" name=".P816"></tt>,
+ <tt><ref id=".P4510" name=".P4510"></tt>,
<tt><ref id=".PC02" name=".PC02"></tt>,
<tt><ref id=".PSC02" name=".PSC02"></tt>
<sect1><tt>.SMART</tt><label id=".SMART"><p>
- Switch on or off smart mode. The command must be followed by a '+' or
- '-' character to switch the option on or off respectively. The default
- is off (that is, the assembler doesn't try to be smart), but this
- default may be changed by the -s switch on the command line.
+ Switch on or off smart mode. The command must be followed by a '+' or '-'
+ character to switch the option on or off respectively. The default is off
+ (that is, the assembler doesn't try to be smart), but this default may be
+ changed by the -s switch on the command line.
+
+ In smart mode the assembler will do the following:
- In smart mode the assembler will track usage of the <tt/REP/ and <tt/SEP/
- instructions in 65816 mode and update the operand sizes accordingly. If
- the operand of such an instruction cannot be evaluated by the assembler
- (for example, because the operand is an imported symbol), a warning is
- issued. Beware: Since the assembler cannot trace the execution flow this
- may lead to false results in some cases. If in doubt, use the <tt/.Inn/ and
- <tt/.Ann/ instructions to tell the assembler about the current settings.
+ <itemize>
+ <item>Track usage of the <tt/REP/ and <tt/SEP/ instructions in 65816 mode
+ and update the operand sizes accordingly. If the operand of such an
+ instruction cannot be evaluated by the assembler (for example, because
+ the operand is an imported symbol), a warning is issued. Beware: Since
+ the assembler cannot trace the execution flow this may lead to false
+ results in some cases. If in doubt, use the <tt/.Inn/ and <tt/.Ann/
+ instructions to tell the assembler about the current settings.
+ <item>In 65816 mode, replace a <tt/RTS/ instruction by <tt/RTL/ if it is
+ used within a procedure declared as <tt/far/, or if the procedure has
+ no explicit address specification, but it is <tt/far/ because of the
+ memory model used.
+ </itemize>
Example:
.smart - ; Stop being smart
</verb></tscreen>
+ See: <tt><ref id=".A16" name=".A16"></tt>,
+ <tt><ref id=".A8" name=".A8"></tt>,
+ <tt><ref id=".I16" name=".I16"></tt>,
+ <tt><ref id=".I8" name=".I8"></tt>
-<sect1><tt>.STRAT</tt><label id=".STRAT"><p>
-
- Builtin function. The function accepts a string and an index as
- arguments and returns the value of the character at the given position
- as an integer value. The index is zero based.
-
- Example:
-
- <tscreen><verb>
- .macro M Arg
- ; Check if the argument string starts with '#'
- .if (.strat (Arg, 0) = '#')
- ...
- .endif
- .endmacro
- </verb></tscreen>
-
-
-<sect1><tt>.STRING</tt><label id=".STRING"><p>
-
- Builtin function. The function accepts an argument in braces and converts
- this argument into a string constant. The argument may be an identifier, or
- a constant numeric value.
- Since you can use a string in the first place, the use of the function may
- not be obvious. However, it is useful in macros, or more complex setups.
+<sect1><tt>.STRUCT</tt><label id=".STRUCT"><p>
- Example:
+ Starts a struct definition. Structs are covered in a separate section named
+ <ref id="structs" name=""Structs and unions"">.
- <tscreen><verb>
- ; Emulate other assemblers:
- .macro section name
- .segment .string(name)
- .endmacro
- </verb></tscreen>
+ See also: <tt><ref id=".ENDSTRUCT" name=".ENDSTRUCT"></tt>,
+ <tt><ref id=".ENDUNION" name=".ENDUNION"></tt>,
+ <tt><ref id=".UNION" name=".UNION"></tt>
-<sect1><tt>.
STRLEN</tt><label id=".STRLEN"><p>
+<sect1><tt>.
TAG</tt><label id=".TAG"><p>
- Builtin function. The function accepts a string argument in braces and
- eveluates to the length of the string.
+ Allocate space for a struct or union.
Example:
- The following macro encodes a string as a pascal style string with
- a leading length byte.
-
<tscreen><verb>
- .macro PString Arg
- .byte .strlen(Arg), Arg
- .endmacro
- </verb></tscreen>
-
-
-<sect1><tt>.SUNPLUS</tt><label id=".SUNPLUS"><p>
-
- Enable the SunPlus instructions set. This command will not work in the
- freeware version of the assembler, because the instruction set is
- "proprietary and confidential".
-
- See: <tt><ref id=".P02" name=".P02"></tt>, <tt><ref id=".PSC02"
- name=".PSC02"></tt>, <tt><ref id=".PC02" name=".PC02"></tt>, and
- <tt><ref id=".P816" name=".P816"></tt>
-
-
-<sect1><tt>.TCOUNT</tt><label id=".TCOUNT"><p>
-
- Builtin function. The function accepts a token list in braces. The
- function result is the number of tokens given as argument.
-
- Example:
-
- The <tt/ldax/ macro accepts the '#' token to denote immidiate addressing (as
- with the normal 6502 instructions). To translate it into two separate 8 bit
- load instructions, the '#' token has to get stripped from the argument:
+ .struct Point
+ xcoord .word
+ ycoord .word
+ .endstruct
- <tscreen><verb>
- .macro ldax arg
- .if (.match (.mid (0, 1, arg), #))
- ; ldax called with immidiate operand
- lda #<(.right (.tcount (arg)-1, arg))
- ldx #>(.right (.tcount (arg)-1, arg))
- .else
- ...
- .endif
- .endmacro
+ .bss
+ .tag Point ; Allocate 4 bytes
</verb></tscreen>
-<sect1><tt>.TIME</tt><label id=".TIME"><p>
-
- Reading this pseudo variable will give a constant integer value that
- represents the current time in POSIX standard (as seconds since the
- Epoch).
-
- It may be used to encode the time of translation somewhere in the created
- code.
-
- Example:
-
- <tscreen><verb>
- .dword .time ; Place time here
- </verb></tscreen>
-
+<sect1><tt>.UNDEF, .UNDEFINE</tt><label id=".UNDEFINE"><p>
-<sect1><tt>.VERSION</tt><label id=".VERSION"><p>
+ Delete a define style macro definition. The command is followed by an
+ identifier which specifies the name of the macro to delete. Macro
+ replacement is switched of when reading the token following the command
+ (otherwise the macro name would be replaced by its replacement list).
- Reading this pseudo variable will give the assembler version according to
- the following formula:
+ See also the <tt><ref id=".DEFINE" name=".DEFINE"></tt> command and
+ section <ref id="macros" name="Macros">.
- VER_MAJOR*$100 + VER_MINOR*$10 + VER_PATCH
- It may be used to encode the assembler version or check the assembler for
- special features not available with older versions.
+<sect1><tt>.UNION</tt><label id=".UNION"><p>
- Example:
+ Starts a union definition. Unions are covered in a separate section named
+ <ref id="structs" name=""Structs and unions"">.
- Version 2.11.1 of the assembler will return $2B1 as numerical constant when
- reading the pseudo variable <tt/.VERSION/.
+ See also: <tt><ref id=".ENDSTRUCT" name=".ENDSTRUCT"></tt>,
+ <tt><ref id=".ENDUNION" name=".ENDUNION"></tt>,
+ <tt><ref id=".STRUCT" name=".STRUCT"></tt>
<sect1><tt>.WARNING</tt><label id=".WARNING"><p>
Force an assembly warning. The assembler will output a warning message
- preceeded by "User warning". This warning will always be output, even if
+ preceded by "User warning". This warning will always be output, even if
other warnings are disabled with the <tt><ref id="option-W" name="-W0"></tt>
command line option.
<tscreen><verb>
.macro jne target
- .local L1
- .ifndef target
- .warning "Forward jump in jne, cannot optimize!"
- beq L1
- jmp target
+ .local L1
+ .ifndef target
+ .warning "Forward jump in jne, cannot optimize!"
+ beq L1
+ jmp target
L1:
.else
- ...
- .endif
+ ...
+ .endif
.endmacro
</verb></tscreen>
- See also the <tt><ref id=".ERROR" name=".ERROR"></tt> and <tt><ref id=".OUT"
- name=".OUT"></tt> directives.
+ See also: <tt><ref id=".ERROR" name=".ERROR"></tt>,
+ <tt><ref id=".FATAL" name=".FATAL"></tt>,
+ <tt><ref id=".OUT" name=".OUT"></tt>
<sect1><tt>.WORD</tt><label id=".WORD"><p>
</verb></tscreen>
-<sect1><tt>.XMATCH</tt><label id=".XMATCH"><p>
-
- Builtin function. Matches two token lists against each other. This is
- most useful within macros, since macros are not stored as strings, but
- as lists of tokens.
-
- The syntax is
-
- <tscreen><verb>
- .XMATCH(<token list #1>, <token list #2>)
- </verb></tscreen>
-
- Both token list may contain arbitrary tokens with the exception of the
- terminator token (comma resp. right parenthesis) and
-
- <itemize>
- <item>end-of-line
- <item>end-of-file
- </itemize>
-
- Often a macro parameter is used for any of the token lists.
-
- The function compares tokens <em/and/ token values. If you need a function
- that just compares the type of tokens, have a look at the <tt><ref
- id=".MATCH" name=".MATCH"></tt> function.
-
- See: <tt><ref id=".MATCH" name=".MATCH"></tt>
-
-
<sect1><tt>.ZEROPAGE</tt><label id=".ZEROPAGE"><p>
Switch to the ZEROPAGE segment and mark it as direct (zeropage) segment.
shortcut for
<tscreen><verb>
- .segment "ZEROPAGE", zeropage
+ .segment "ZEROPAGE": zeropage
</verb></tscreen>
Because of the "zeropage" attribute, labels declared in this segment are
<sect1>Macros without parameters<p>
-In it's simplest form, a macro does not have parameters. Here's an
+In its simplest form, a macro does not have parameters. Here's an
example:
<tscreen><verb>
- .macro asr ; Arithmetic shift right
- cmp #$80 ; Put bit 7 into carry
- ror ; Rotate right with carry
- .endmacro
+.macro asr ; Arithmetic shift right
+ cmp #$80 ; Put bit 7 into carry
+ ror ; Rotate right with carry
+.endmacro
</verb></tscreen>
The macro above consists of two real instructions, that are inserted into
by using the name, like this:
<tscreen><verb>
- lda $2010
- asr
- sta $2010
+ lda $2010
+ asr
+ sta $2010
</verb></tscreen>
When using macro parameters, macros can be even more useful:
<tscreen><verb>
- .macro inc16 addr
- clc
- lda addr
- adc #$01
- sta addr
- lda addr+1
- adc #$00
- sta addr+1
- .endmacro
+.macro inc16 addr
+ clc
+ lda addr
+ adc #<$0001
+ sta addr
+ lda addr+1
+ adc #>$0001
+ sta addr+1
+.endmacro
</verb></tscreen>
-When calling the macro, you may give a parameter, and each occurence of
+When calling the macro, you may give a parameter, and each occurrence of
the name "addr" in the macro definition will be replaced by the given
parameter. So
<tscreen><verb>
- inc16 $1000
+ inc16 $1000
</verb></tscreen>
will be expanded to
<tscreen><verb>
- clc
- lda $1000
- adc #$01
- sta $1000
- lda $1000+1
- adc #$00
- sta $1000+1
+ clc
+ lda $1000
+ adc #<$0001
+ sta $1000
+ lda $1000+1
+ adc #>$0001
+ sta $1000+1
</verb></tscreen>
A macro may have more than one parameter, in this case, the parameters
are separated by commas. You are free to give less parameters than the
macro actually takes in the definition. You may also leave intermediate
parameters empty. Empty parameters are replaced by empty space (that is,
-they are removed when the macro is exanded). If you have a look at our
+they are removed when the macro is expanded). If you have a look at our
macro definition above, you will see, that replacing the "addr" parameter
by nothing will lead to wrong code in most lines. To help you, writing
macros with a variable parameter list, there are some control commands:
Look at this example:
<tscreen><verb>
- .macro ldaxy a, x, y
- .ifnblank a
- lda #a
- .endif
- .ifnblank x
- ldx #x
- .endif
- .ifnblank y
- ldy #y
- .endif
- .endmacro
+.macro ldaxy a, x, y
+.ifnblank a
+ lda #a
+.endif
+.ifnblank x
+ ldx #x
+.endif
+.ifnblank y
+ ldy #y
+.endif
+.endmacro
</verb></tscreen>
-This macro may be called as follows:
+That macro may be called as follows:
<tscreen><verb>
- ldaxy 1, 2, 3 ; Load all three registers
+ ldaxy 1, 2, 3 ; Load all three registers
- ldaxy 1, , 3 ; Load only a and y
+ ldaxy 1, , 3 ; Load only a and y
- ldaxy , , 3 ; Load y only
+ ldaxy , , 3 ; Load y only
</verb></tscreen>
-There's another helper command for determining, which macro parameters are
-valid: <tt><ref id=".PARAMCOUNT" name=".PARAMCOUNT"></tt> This command is
-replaced by the parameter count given, <em/including/ intermediate empty macro
+There's another helper command for determining which macro parameters are
+valid: <tt><ref id=".PARAMCOUNT" name=".PARAMCOUNT"></tt>. That command is
+replaced by the parameter count given, <em/including/ explicitly empty
parameters:
<tscreen><verb>
- ldaxy 1 ; .PARAMCOUNT = 1
- ldaxy 1,,3 ; .PARAMCOUNT = 3
- ldaxy 1,2 ; .PARAMCOUNT = 2
- ldaxy 1, ; .PARAMCOUNT = 2
- ldaxy 1,2,3 ; .PARAMCOUNT = 3
+ ldaxy 1 ; .PARAMCOUNT = 1
+ ldaxy 1,,3 ; .PARAMCOUNT = 3
+ ldaxy 1,2 ; .PARAMCOUNT = 2
+ ldaxy 1, ; .PARAMCOUNT = 2
+ ldaxy 1,2,3 ; .PARAMCOUNT = 3
+</verb></tscreen>
+
+Macro parameters may optionally be enclosed into curly braces. This allows the
+inclusion of tokens that would otherwise terminate the parameter (the comma in
+case of a macro parameter).
+
+<tscreen><verb>
+.macro foo arg1, arg2
+ ...
+.endmacro
+
+ foo ($00,x) ; Two parameters passed
+ foo {($00,x)} ; One parameter passed
+</verb></tscreen>
+
+In the first case, the macro is called with two parameters: '<tt/($00/'
+and '<tt/x)/'. The comma is not passed to the macro, because it is part of the
+calling sequence, not the parameters.
+
+In the second case, '<tt/($00,x)/' is passed to the macro; this time,
+including the comma.
+
+
+<sect1>Detecting parameter types<p>
+
+Sometimes it is nice to write a macro that acts differently depending on the
+type of the argument supplied. An example would be a macro that loads a 16 bit
+value from either an immediate operand, or from memory. The <tt/<ref
+id=".MATCH" name=".MATCH">/ and <tt/<ref id=".XMATCH" name=".XMATCH">/
+functions will allow you to do exactly this:
+
+<tscreen><verb>
+.macro ldax arg
+ .if (.match (.left (1, {arg}), #))
+ ; immediate mode
+ lda #<(.right (.tcount ({arg})-1, {arg}))
+ ldx #>(.right (.tcount ({arg})-1, {arg}))
+ .else
+ ; assume absolute or zero page
+ lda arg
+ ldx 1+(arg)
+ .endif
+.endmacro
+</verb></tscreen>
+
+Using the <tt/<ref id=".MATCH" name=".MATCH">/ function, the macro is able to
+check if its argument begins with a hash mark. If so, two immediate loads are
+emitted, Otherwise a load from an absolute zero page memory location is
+assumed. Please note how the curly braces are used to enclose parameters to
+pseudo functions handling token lists. This is necessary, because the token
+lists may include commas or parens, which would be treated by the assembler
+as end-of-list.
+
+The macro can be used as
+
+<tscreen><verb>
+foo: .word $5678
+...
+ ldax #$1234 ; X=$12, A=$34
+...
+ ldax foo ; X=$56, A=$78
</verb></tscreen>
Macros may be used recursively:
<tscreen><verb>
- .macro push r1, r2, r3
- lda r1
- pha
- .if .paramcount > 1
- push r2, r3
- .endif
- .endmacro
+.macro push r1, r2, r3
+ lda r1
+ pha
+.ifnblank r2
+ push r2, r3
+.endif
+.endmacro
</verb></tscreen>
-There's also a special macro to help writing recursive macros: <tt><ref
-id=".EXITMACRO" name=".EXITMACRO"></tt> This command will stop macro expansion
-immidiately:
+There's also a special macro command to help with writing recursive macros:
+<tt><ref id=".EXITMACRO" name=".EXITMACRO"></tt>. That command will stop macro
+expansion immediately:
<tscreen><verb>
- .macro push r1, r2, r3, r4, r5, r6, r7
- .ifblank r1
- ; First parameter is empty
- .exitmacro
- .else
- lda r1
- pha
- .endif
- push r2, r3, r4, r5, r6, r7
- .endmacro
+.macro push r1, r2, r3, r4, r5, r6, r7
+.ifblank r1
+ ; First parameter is empty
+ .exitmacro
+.else
+ lda r1
+ pha
+.endif
+ push r2, r3, r4, r5, r6, r7
+.endmacro
</verb></tscreen>
-When expanding this macro, the expansion will push all given parameters
+When expanding that macro, the expansion will push all given parameters
until an empty one is encountered. The macro may be called like this:
<tscreen><verb>
- push $20, $21, $32 ; Push 3 ZP locations
- push $21 ; Push one ZP location
+ push $20, $21, $32 ; Push 3 ZP locations
+ push $21 ; Push one ZP location
</verb></tscreen>
Have a look at the inc16 macro above. Here is it again:
<tscreen><verb>
- .macro inc16 addr
- clc
- lda addr
- adc #$01
- sta addr
- lda addr+1
- adc #$00
- sta addr+1
- .endmacro
+.macro inc16 addr
+ clc
+ lda addr
+ adc #<$0001
+ sta addr
+ lda addr+1
+ adc #>$0001
+ sta addr+1
+.endmacro
</verb></tscreen>
If you have a closer look at the code, you will notice, that it could be
written more efficiently, like this:
<tscreen><verb>
- .macro inc16 addr
- inc addr
- bne Skip
- inc addr+1
- Skip:
- .endmacro
+.macro inc16 addr
+ inc addr
+ bne Skip
+ inc addr+1
+Skip:
+.endmacro
</verb></tscreen>
-But imagine what happens, if you use this macro twice? Since the label
-"Skip" has the same name both times, you get a "duplicate symbol" error.
-Without a way to circumvent this problem, macros are not as useful, as
-they could be. One solution is, to start a new lexical block inside the
-macro:
+But imagine what happens, if you use this macro twice? Since the label "Skip"
+has the same name both times, you get a "duplicate symbol" error. Without a
+way to circumvent this problem, macros are not as useful, as they could be.
+One possible solution is the command <tt><ref id=".LOCAL" name=".LOCAL"></tt>.
+It declares one or more symbols as local to the macro expansion. The names of
+local variables are replaced by a unique name in each separate macro
+expansion. So we can solve the problem above by using <tt/.LOCAL/:
<tscreen><verb>
- .macro inc16 addr
- .proc
- inc addr
- bne Skip
- inc addr+1
- Skip:
- .endproc
- .endmacro
+.macro inc16 addr
+ .local Skip ; Make Skip a local symbol
+ inc addr
+ bne Skip
+ inc addr+1
+Skip: ; Not visible outside
+.endmacro
</verb></tscreen>
-Now the label is local to the block and not visible outside. However,
-sometimes you want a label inside the macro to be visible outside. To make
-that possible, there's a new command that's only usable inside a macro
-definition: <tt><ref id=".LOCAL" name=".LOCAL"></tt>. <tt/.LOCAL/ declares one
-or more symbols as local to the macro expansion. The names of local variables
-are replaced by a unique name in each separate macro expansion. So we could
-also solve the problem above by using <tt/.LOCAL/:
+Another solution is of course to start a new lexical block inside the macro
+that hides any labels:
<tscreen><verb>
- .macro inc16 addr
- .local Skip ; Make Skip a local symbol
- clc
- lda addr
- adc #$01
- sta addr
- bcc Skip
- inc addr+1
- Skip: ; Not visible outside
- .endmacro
+.macro inc16 addr
+.proc
+ inc addr
+ bne Skip
+ inc addr+1
+Skip:
+.endproc
+.endmacro
</verb></tscreen>
some things may be done with both macro types, each type has special
usages. The types complement each other.
+<item> Parentheses work differently from C macros.
+ The common practice of wrapping C macros in parentheses may cause
+ unintended problems here, such as accidentally implying an
+ indirect addressing mode. While the definition of a macro requires
+ parentheses around its argument list, when invoked they should not be
+ included.
+
</itemize>
Let's look at a few examples to make the advantages and disadvantages
following <tt/.DEFINE/:
<tscreen><verb>
- .define EQU =
+.define EQU =
- foo EQU $1234 ; This is accepted now
+foo EQU $1234 ; This is accepted now
</verb></tscreen>
You may use the directive to define string constants used elsewhere:
<tscreen><verb>
- ; Define the version number
- .define VERSION "12.3a"
+; Define the version number
+.define VERSION "12.3a"
- ; ... and use it
- .asciiz VERSION
+ ; ... and use it
+ .asciiz VERSION
</verb></tscreen>
Macros with parameters may also be useful:
<tscreen><verb>
- .define DEBUG(message) .out message
+.define DEBUG(message) .out message
- DEBUG "Assembling include file #3"
+ DEBUG "Assembling include file #3"
</verb></tscreen>
-Note that, while formal parameters have to be placed in braces, this is
-not true for the actual parameters. Beware: Since the assembler cannot
-detect the end of one parameter, only the first token is used. If you
-don't like that, use classic macros instead:
+Note that, while formal parameters have to be placed in parentheses,
+the actual argument used when invoking the macro should not be.
+The invoked arguments are separated by commas only, if parentheses are
+used by accident they will become part of the replaced token.
+
+If you wish to have an expression follow the macro invocation, the
+last parameter can be enclosed in curly braces {} to indicate the end of that
+argument.
+
+Examples:
<tscreen><verb>
- .macro message
- .out message
- .endmacro
+.define COMBINE(ta,tb,tc) ta+tb*10+tc*100
+
+.word COMBINE 5,6,7 ; 5+6*10+7*100 = 765
+.word COMBINE(5,6,7) ; (5+6*10+7)*100 = 7200 ; incorrect use of parentheses
+.word COMBINE 5,6,7+1 ; 5+6*10+7+1*100 = 172
+.word COMBINE 5,6,{7}+1 ; 5+6*10+7*100+1 = 766 ; {} encloses the argument
+.word COMBINE 5,6-2,7 ; 5+6-2*10+7*100 = 691
+.word COMBINE 5,(6-2),7 ; 5+(6-2)*10+7*100 = 745
+.word COMBINE 5,6,7+COMBINE 0,1,2 ; 5+6*10+7+0+1*10+2*100*100 = 20082
+.word COMBINE 5,6,{7}+COMBINE 0,1,2 ; 5+6*10+7*100+0+1*10+2*100 = 975
</verb></tscreen>
-(This is an example where a problem can be solved with both macro types).
+With C macros it is common to enclose the results in parentheses to
+prevent unintended interactions with the text of the arguments, but
+additional care must be taken in this assembly context where parentheses
+may alter the meaning of a statement. In particular, indirect addressing modes
+may be accidentally implied:
+
+<tscreen><verb>
+.define DUO(ta,tb) (ta+(tb*10))
+
+ lda DUO(5,4), Y ; LDA (indirect), Y
+ lda 0+DUO(5,4), Y ; LDA absolute indexed, Y
+</verb></tscreen>
<sect1>Characters in macros<p>
be sure to take the translation into account.
+<sect1>Deleting macros<p>
+
+Macros can be deleted. This will not work if the macro that should be deleted
+is currently expanded as in the following non-working example:
+
+<tscreen><verb>
+.macro notworking
+ .delmacro notworking
+.endmacro
+
+ notworking ; Will not work
+</verb></tscreen>
+
+The commands to delete classic and define style macros differ. Classic macros
+can be deleted by use of <tt><ref id=".DELMACRO" name=".DELMACRO"></tt>, while
+for <tt><ref id=".DEFINE" name=".DEFINE"></tt> style macros, <tt><ref
+id=".UNDEFINE" name=".UNDEFINE"></tt> must be used. Example:
+
+<tscreen><verb>
+.define value 1
+.macro mac
+ .byte 2
+.endmacro
+
+ .byte value ; Emit one byte with value 1
+ mac ; Emit another byte with value 2
+
+.undefine value
+.delmacro mac
+
+ .byte value ; Error: Unknown identifier
+ mac ; Error: Missing ":"
+</verb></tscreen>
+
+A separate command for <tt>.DEFINE</tt> style macros was necessary, because
+the name of such a macro is replaced by its replacement list on a very low
+level. To get the actual name, macro replacement has to be switched off when
+reading the argument to <tt>.UNDEFINE</tt>. This does also mean that the
+argument to <tt>.UNDEFINE</tt> is not allowed to come from another
+<tt>.DEFINE</tt>. All this is not necessary for classic macros, so having two
+different commands increases flexibility.
+
<sect>Macro packages<label id="macropackages"><p>
<sect1><tt>.MACPACK generic</tt><p>
-This macro package defines macros that are useful in almost any program.
-Currently, two macros are defined:
+This macro package defines macroes that are useful in almost any program.
+Currently defined macroes are:
<tscreen><verb>
- .macro add Arg
+ .macro add Arg ; add without carry
clc
- adc Arg
- .endmacro
-
- .macro sub Arg
- sec
- sbc Arg
- .endmacro
+ adc Arg
+ .endmacro
+
+ .macro sub Arg ; subtract without borrow
+ sec
+ sbc Arg
+ .endmacro
+
+ .macro bge Arg ; branch on greater-than or equal
+ bcs Arg
+ .endmacro
+
+ .macro blt Arg ; branch on less-than
+ bcc Arg
+ .endmacro
+
+ .macro bgt Arg ; branch on greater-than
+ .local L
+ beq L
+ bcs Arg
+ L:
+ .endmacro
+
+ .macro ble Arg ; branch on less-than or equal
+ beq Arg
+ bcc Arg
+ .endmacro
+
+ .macro bnz Arg ; branch on not zero
+ bne Arg
+ .endmacro
+
+ .macro bze Arg ; branch on zero
+ beq Arg
+ .endmacro
</verb></tscreen>
scheme:
<tscreen><verb>
- .macro jeq Target
+ .macro jeq Target
.if .def(Target) .and ((*+2)-(Target) <= 127)
beq Target
.else
- bne *+5
- jmp Target
+ bne *+5
+ jmp Target
.endif
.endmacro
</verb></tscreen>
+<sect1><tt>.MACPACK apple2</tt><p>
+
+This macro package defines a macro named <tt/scrcode/. It takes a string
+as argument and places this string into memory translated into screen codes.
+
+
+<sect1><tt>.MACPACK atari</tt><p>
+
+This macro package defines a macro named <tt/scrcode/. It takes a string
+as argument and places this string into memory translated into screen codes.
+
+
<sect1><tt>.MACPACK cbm</tt><p>
-The cbm macro package will define a macro named <tt/scrcode/. It takes a
-string as argument and places this string into memory translated into screen
-codes.
+This macro package defines a macro named <tt/scrcode/. It takes a string
+as argument and places this string into memory translated into screen codes.
<sect1><tt>.MACPACK cpu</tt><p>
CPU_65SC02
CPU_65C02
CPU_65816
- CPU_SUNPLUS
+ CPU_SWEET16
+ CPU_HUC6280
+ CPU_4510
</verb></tscreen>
is defined. These constants may be used to determine the exact type of the
CPU_ISET_65SC02
CPU_ISET_65C02
CPU_ISET_65816
- CPU_ISET_SUNPLUS
+ CPU_ISET_SWEET16
+ CPU_ISET_HUC6280
+ CPU_ISET_4510
</verb></tscreen>
The value read from the <tt/<ref id=".CPU" name=".CPU">/ pseudo variable may
CPUs (the latter two are upwards compatible to the 65SC02).
+<sect1><tt>.MACPACK module</tt><p>
+
+This macro package defines a macro named <tt/module_header/. It takes an
+identifier as argument and is used to define the header of a module both
+in the dynamic and static variant.
+
+
+
+<sect>Predefined constants<label id="predefined-constants"><p>
+
+For better orthogonality, the assembler defines similar symbols as the
+compiler, depending on the target system selected:
+
+<itemize>
+<item><tt/__APPLE2__/ - Target system is <tt/apple2/ or <tt/apple2enh/
+<item><tt/__APPLE2ENH__/ - Target system is <tt/apple2enh/
+<item><tt/__ATARI2600__/ - Target system is <tt/atari2600/
+<item><tt/__ATARI5200__/ - Target system is <tt/atari5200/
+<item><tt/__ATARI__/ - Target system is <tt/atari/ or <tt/atarixl/
+<item><tt/__ATARIXL__/ - Target system is <tt/atarixl/
+<item><tt/__ATMOS__/ - Target system is <tt/atmos/
+<item><tt/__BBC__/ - Target system is <tt/bbc/
+<item><tt/__C128__/ - Target system is <tt/c128/
+<item><tt/__C16__/ - Target system is <tt/c16/ or <tt/plus4/
+<item><tt/__C64__/ - Target system is <tt/c64/
+<item><tt/__CBM__/ - Target is a Commodore system
+<item><tt/__CBM510__/ - Target system is <tt/cbm510/
+<item><tt/__CBM610__/ - Target system is <tt/cbm610/
+<item><tt/__GEOS__/ - Target is a GEOS system
+<item><tt/__GEOS_APPLE__/ - Target system is <tt/geos-apple/
+<item><tt/__GEOS_CBM__/ - Target system is <tt/geos-cbm/
+<item><tt/__LUNIX__/ - Target system is <tt/lunix/
+<item><tt/__LYNX__/ - Target system is <tt/lynx/
+<item><tt/__NES__/ - Target system is <tt/nes/
+<item><tt/__OSIC1P__/ - Target system is <tt/osic1p/
+<item><tt/__PET__/ - Target system is <tt/pet/
+<item><tt/__PLUS4__/ - Target system is <tt/plus4/
+<item><tt/__SIM6502__/ - Target system is <tt/sim6502/
+<item><tt/__SIM65C02__/ - Target system is <tt/sim65c02/
+<item><tt/__SUPERVISION__/ - Target system is <tt/supervision/
+<item><tt/__VIC20__/ - Target system is <tt/vic20/
+</itemize>
+
+
+<sect>Structs and unions<label id="structs"><p>
+
+<sect1>Structs and unions Overview<p>
+
+Structs and unions are special forms of <ref id="scopes" name="scopes">. They
+are to some degree comparable to their C counterparts. Both have a list of
+members. Each member allocates storage and may optionally have a name, which,
+in case of a struct, is the offset from the beginning and, in case of a union,
+is always zero.
+
+
+<sect1>Declaration<p>
+
+Here is an example for a very simple struct with two members and a total size
+of 4 bytes:
+
+<tscreen><verb>
+ .struct Point
+ xcoord .word
+ ycoord .word
+ .endstruct
+</verb></tscreen>
+
+A union shares the total space between all its members, its size is the same
+as that of the largest member. The offset of all members relative to the union
+is zero.
+
+<tscreen><verb>
+ .union Entry
+ index .word
+ ptr .addr
+ .endunion
+</verb></tscreen>
+
+A struct or union must not necessarily have a name. If it is anonymous, no
+local scope is opened, the identifiers used to name the members are placed
+into the current scope instead.
+
+A struct may contain unnamed members and definitions of local structs. The
+storage allocators may contain a multiplier, as in the example below:
+
+<tscreen><verb>
+ .struct Circle
+ .struct Point
+ .word 2 ; Allocate two words
+ .endstruct
+ Radius .word
+ .endstruct
+</verb></tscreen>
+
+
+<sect1>The <tt/.TAG/ keyword<p>
+
+Using the <ref id=".TAG" name=".TAG"> keyword, it is possible to reserve space
+for an already defined struct or unions within another struct:
+
+<tscreen><verb>
+ .struct Point
+ xcoord .word
+ ycoord .word
+ .endstruct
+
+ .struct Circle
+ Origin .tag Point
+ Radius .byte
+ .endstruct
+</verb></tscreen>
+
+Space for a struct or union may be allocated using the <ref id=".TAG"
+name=".TAG"> directive.
+
+<tscreen><verb>
+ C: .tag Circle
+</verb></tscreen>
+
+Currently, members are just offsets from the start of the struct or union. To
+access a field of a struct, the member offset has to be added to the address
+of the struct itself:
+
+<tscreen><verb>
+ lda C+Circle::Radius ; Load circle radius into A
+</verb></tscreen>
+
+This may change in a future version of the assembler.
+
+
+<sect1>Limitations<p>
+
+Structs and unions are currently implemented as nested symbol tables (in fact,
+they were a by-product of the improved scoping rules). Currently, the
+assembler has no idea of types. This means that the <ref id=".TAG"
+name=".TAG"> keyword will only allocate space. You won't be able to initialize
+variables declared with <ref id=".TAG" name=".TAG">, and adding an embedded
+structure to another structure with <ref id=".TAG" name=".TAG"> will not make
+this structure accessible by using the '::' operator.
+
+
<sect>Module constructors/destructors<label id="condes"><p>
useful for assembler programs.
-<sect1>Module
overview<p>
+<sect1>Module
constructors/destructors Overview<p>
-Using the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
-id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> keywords it it possible to export
-functions in a special way. The linker is able to generate tables with all
-functions of a specific type. Such a table will <em>only</em> include symbols
-from object files that are linked into a specific executable. This may be used
-to add initialization and cleanup code for library modules.
+Using the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt>, <tt><ref
+id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> and <tt><ref id=".INTERRUPTOR"
+name=".INTERRUPTOR"></tt> keywords it is possible to export functions in a
+special way. The linker is able to generate tables with all functions of a
+specific type. Such a table will <em>only</em> include symbols from object
+files that are linked into a specific executable. This may be used to add
+initialization and cleanup code for library modules, or a table of interrupt
+handler functions.
The C heap functions are an example where module initialization code is used.
All heap functions (<tt>malloc</tt>, <tt>free</tt>, ...) work with a few
<sect1>Calling order<p>
-Both, constructors and destructors are sorted in increasing priority order by
-the linker when using one of the builtin linker configurations, so the
-functions with lower priorities come first and are followed by those with
-higher priorities. The C library runtime subroutine that walks over the
-constructor and destructor tables calls the functions starting from the top of
-the table - which means that functions with a high priority are called first.
+The symbols are sorted in increasing priority order by the linker when using
+one of the builtin linker configurations, so the functions with lower
+priorities come first and are followed by those with higher priorities. The C
+library runtime subroutine that walks over the function tables calls the
+functions starting from the top of the table - which means that functions with
+a high priority are called first.
-So when using the C runtime, both constructors and destructors are called with
-high priority functions first, followed by low priority functions.
+So when using the C runtime, functions are called with high priority functions
+first, followed by low priority functions.
<sect1>Pitfalls<p>
-When creating and using module constructors and destructors, please take care
-of the following:
+When using these special symbols, please take care of the following:
<itemize>
The linker will only generate function tables, it will not generate code to
call these functions. If you're using the feature in some other than the
existing C environments, you have to write code to call all functions in a
-linker generated table yourself. See the <tt>condes</tt> module in the C
-runtime for an example on how to do this.
+linker generated table yourself. See the <tt/condes/ and <tt/callirq/ modules
+in the C runtime for an example on how to do this.
<item>
The linker will only add addresses of functions that are in modules linked to
the executable. This means that you have to be careful where to place the
-condes functions. If initialization is needed for a group of functions, be
-sure to place the initialization function into a module that is linked in
+condes functions. If initialization or an irq handler is needed for a group of
+functions, be sure to place the function into a module that is linked in
regardless of which function is called by the user.
<item>
<item>
Constructors and destructors may have priorities. These priorities determine
-the order of the functions in the table. If your intialization or cleanup code
+the order of the functions in the table. If your initialization or cleanup code
does depend on other initialization or cleanup code, you have to choose the
priority for the functions accordingly.
<item>
-Besides the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
-id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> statements, there is also a more
-generic command: <tt><ref id=".CONDES" name=".CONDES"></tt>. This allows to
-specify an additional type. Predefined types are 0 (constructor) and 1
-(destructor). The linker generates a separate table for each type on request.
+Besides the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt>, <tt><ref
+id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> and <tt><ref id=".INTERRUPTOR"
+name=".INTERRUPTOR"></tt> statements, there is also a more generic command:
+<tt><ref id=".CONDES" name=".CONDES"></tt>. This allows to specify an
+additional type. Predefined types are 0 (constructor), 1 (destructor) and 2
+(interruptor). The linker generates a separate table for each type on request.
</itemize>
<item>Replace all program counter assignments (which are not possible in ca65
by default, and the respective emulation feature works different from what
-you'd expect) by another way to skip to another memory location, for example
-the <tt><ref id=".RES" name=".RES"></tt>directive.
+you'd expect) by another way to skip to memory locations, for example the
+<tt><ref id=".RES" name=".RES"></tt> directive.
<tscreen><verb>
; *=$2000
.res $2000-* ; reserve memory up to $2000
</verb></tscreen>
-notice that other than the original TASS, ca65 can never move the
-programmcounter backwards - think of it as if you are assembling to disc with
-TASS.
+Please note that other than the original TASS, ca65 can never move the program
+counter backwards - think of it as if you are assembling to disk with TASS.
-<item>Conditional assembly (<tt/.ifeq//<tt/.endif//<tt/.gogo/ etc.) must be
+<item>Conditional assembly (<tt/.ifeq//<tt/.endif//<tt/.goto/ etc.) must be
rewritten to match ca65 syntax. Most importantly notice that due to the lack
of <tt/.goto/, everything involving loops must be replaced by
<tt><ref id=".REPEAT" name=".REPEAT"></tt>.
cl65 --start-addr 0x0ffe -t none myprog.s -o myprog.prg
</verb></tscreen>
-notice that you need to use the actual start address minus two, since two
-bytes are used for the cbm load address.
+Note that you need to use the actual start address minus two, since two bytes
+are used for the cbm load address.
</enum>
-<sect>Bugs/Feedback<p>
-
-If you have problems using the assembler, if you find any bugs, or if
-you're doing something interesting with the assembler, I would be glad to
-hear from you. Feel free to contact me by email
-(<htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">).
-
-
-
<sect>Copyright<p>
-ca65 (and all cc65 binutils) are (C) Copyright 1998-2001 Ullrich von
+ca65 (and all cc65 binutils) are (C) Copyright 1998-2003 Ullrich von
Bassewitz. For usage of the binaries and/or sources the following
conditions do apply:
</article>
-
-
-
projects / cc65 / blobdiff