-<!doctype linuxdoc system>
+<!doctype linuxdoc system> <!-- -*- text-mode -*- -->
<article>
<title>ca65 Users Guide
-g Add debug info to object file
-h Help (this text)
-i Ignore case of symbols
- -l Create a listing if assembly was ok
+ -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
--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
+ --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
--macpack-dir dir Set a macro package directory
--memory-model model Set the memory model
<label id="option-l">
- <tag><tt>-l, --listing</tt></tag>
+ <tag><tt>-l name, --listing name</tt></tag>
- 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.
+ 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.
<label id="option--list-bytes">
<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>
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 <htmlurl
-url="http://oxyron.net/graham/opcodes02.html"
-name="http://oxyron.net/graham/opcodes02.html">. Please note that only the
+url="http://www.oxyron.de/html/opcodes02.html"
+name="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>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> 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>
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>
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
+ Clear: lda #$00 ; Global label
+ ldy #$20
+ @Loop: sta Mem,y ; Local label
+ dey
+ bne @Loop ; Ok
+ rts
Sub: ... ; New global label
- bne @Loop ; ERROR: Unknown identifier!
+ bne @Loop ; ERROR: Unknown identifier!
</verb></tscreen>
<sect1>Unnamed labels<p>
understand this:
<tscreen><verb>
- : lda (ptr1),y ; #1
- cmp (ptr2),y
- bne :+ ; -> #2
- tax
- beq :+++ ; -> #4
- iny
- bne :- ; -> #1
- inc ptr1+1
- inc ptr2+1
- bne :- ; -> #1
-
- : bcs :+ ; #2 -> #3
- ldx #$FF
- rts
-
- : ldx #$01 ; #3
- : rts ; #4
+ : lda (ptr1),y ; #1
+ cmp (ptr2),y
+ bne :+ ; -> #2
+ tax
+ beq :+++ ; -> #4
+ iny
+ bne :- ; -> #1
+ inc ptr1+1
+ inc ptr2+1
+ bne :- ; -> #1
+
+ : bcs :+ ; #2 -> #3
+ ldx #$FF
+ rts
+
+ : ldx #$01 ; #3
+ : rts ; #4
</verb></tscreen>
As you can see from the example, unnamed labels will make even short
<sect1>Using macros to define labels and constants<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
+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"
+ .DEFINE two 2
+ .DEFINE version "SOS V2.3"
- four = two * two ; Ok
- .byte version ; Ok
+ four = two * two ; Ok
+ .byte version ; Ok
- .PROC ; Start local scope
- two = 3 ; Will give "2 = 3" - invalid!
- .ENDPROC
+ .PROC ; Start local scope
+ two = 3 ; Will give "2 = 3" - invalid!
+ .ENDPROC
</verb></tscreen>
either a string or an expression.
+<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.
<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>
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>.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>
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/
<sect1><tt>.ERROR</tt><label id=".ERROR"><p>
Force an assembly error. The assembler will output an error message
- preceded 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 immediately. This command is often useful in
- recursive macros. See separate section <ref id="macros" name="Macros">.
+ 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>
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
at character is not allowed to start an identifier, even with this
feature enabled.
- <tag><tt>c_comments</tt></tag>
+ <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
dollar character is not allowed to start an identifier, even with this
feature enabled.
- <tag><tt>dollar_is_pc</tt></tag>
+ <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).
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>loose_string_term</tt></tag>
+ <tag><tt>loose_string_term</tt><label id="loose_string_term"></tag>
Accept single quotes as well as double quotes as terminators for string
constants.
- <tag><tt>missing_char_term</tt></tag>
+ <tag><tt>missing_char_term</tt><label id="missing_char_term"></tag>
Accept single quoted character constants where the terminating quote is
missing.
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/
is enabled). Such an assignment is handled identical to the <tt><ref
removing the lines with the assignments may also be an option when porting
code written for older assemblers).
- <tag><tt>ubiquitous_idents</tt></tag>
+ <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
<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.
+ that are macro parameters. A macro definition is terminated by <tt><ref
+ id=".ENDMACRO" name=".ENDMACRO"></tt>.
- See section <ref id="macros" name="Macros">.
+ Example:
+
+ <tscreen><verb>
+ .macro ldax arg ; Define macro ldax
+ lda arg
+ ldx arg+1
+ </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 section <ref id="macros" name="Macros">.
<sect1><tt>.ORG</tt><label id=".ORG"><p>
.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>
id=".RODATA" name=".RODATA"></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
Starts a struct definition. Structs are covered in a separate section named
<ref id="structs" name=""Structs and unions"">.
- See: <tt><ref id=".ENDSTRUCT" name=".ENDSTRUCT"></tt>
+ 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>.SUNPLUS</tt><label id=".SUNPLUS"><p>
</verb></tscreen>
+<sect1><tt>.UNDEF, .UNDEFINE</tt><label id=".UNDEFINE"><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).
+
+ See also the <tt><ref id=".DEFINE" name=".DEFINE"></tt> command and
+ section <ref id="macros" name="Macros">.
+
+
+<sect1><tt>.UNION</tt><label id=".UNION"><p>
+
+ Starts a union definition. Unions are covered in a separate section named
+ <ref id="structs" name=""Structs and unions"">.
+
+ 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
<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>
<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
+ 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 #$01
+ sta addr
+ lda addr+1
+ adc #$00
+ sta addr+1
+ .endmacro
</verb></tscreen>
When calling the macro, you may give a parameter, and each occurrence of
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 #$01
+ sta $1000
+ lda $1000+1
+ adc #$00
+ sta $1000+1
</verb></tscreen>
A macro may have more than one parameter, in this case, the parameters
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:
<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
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
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>
be omitted.
<item> Since <tt><ref id=".DEFINE" name=".DEFINE"></tt> style macros may not
- contain end-of-line tokens, there are things that cannot be done. They
+ contain end-of-line tokens, there are things that cannot be done. They
may not contain several processor instructions for example. So, while
some things may be done with both macro types, each type has special
usages. The types complement each other.
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:
+Currently defined macros are:
<tscreen><verb>
.macro add Arg
clc
- adc Arg
- .endmacro
+ adc Arg
+ .endmacro
- .macro sub Arg
- sec
- sbc Arg
- .endmacro
+ .macro sub Arg
+ sec
+ sbc Arg
+ .endmacro
+
+ .macro bge Arg
+ bcs Arg
+ .endmacro
+
+ .macro blt Arg
+ bcc Arg
+ .endmacro
+
+ .macro bgt Arg
+ .local L
+ beq L
+ bcs Arg
+ L:
+ .endmacro
+
+ .macro ble Arg
+ beq Arg
+ bcc 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 atari</tt><p>
+
+The atari 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.
+
+
<sect1><tt>.MACPACK cbm</tt><p>
The cbm macro package will define a macro named <tt/scrcode/. It takes a
</verb></tscreen>
A union shares the total space between all its members, its size is the same
-as that of the largest member.
+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
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