<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
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
+ an error message. In the latter case, generation of the output file is
suppressed in both the assembler and linker.
.autoimport + ; Switch on auto import
</verb></tscreen>
+<sect1><tt>.BANKBYTES</tt><label id=".BANKBYTES"><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.
+
+ 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>
+ 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>
<descrip>
- <tag><tt>at_in_identifiers</tt></tag>
+ <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
*/ sta $82
</verb></tscreen>
- <tag><tt>dollar_in_identifiers</tt></tag>
+ <tag><tt>dollar_in_identifiers</tt><label id="dollar_in_identifiers"></tag>
Accept the dollar sign (`$') as a valid character in identifiers. The
- at character is not allowed to start an identifier, even with this
+ dollar character is not allowed to start an identifier, even with this
feature enabled.
<tag><tt>dollar_is_pc</tt></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>leading_dot_in_identifiers</tt></tag>
+ <tag><tt>leading_dot_in_identifiers</tt><label id="leading_dot_in_identifiers"></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
.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>
</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
compiler, depending on the target system selected:
<itemize>
-<item><tt/__ACE__/ - Target system is <tt/ace/
<item><tt/__APPLE2__/ - Target system is <tt/apple2/
<item><tt/__APPLE2ENH__/ - Target system is <tt/apple2enh/
<item><tt/__ATARI__/ - Target system is <tt/atari/
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