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cc65 的编译器文档

<H2><A NAME=".PUSHSEG"></A> <A NAME="ss10.77">10.77</A> <A HREF="ca65.html#toc10.77"><CODE>.PUSHSEG</CODE></A>
</H2>


<P>Push the currently active segment onto a stack. The entries on the stack
include the name of the segment and the segment type. The stack has a size
of 16 entries.</P>
<P><CODE>.PUSHSEG</CODE> allows together with <CODE>
<A HREF="#.POPSEG">.POPSEG</A></CODE>
to switch to another segment and to restore the old segment later, without
even knowing the name and type of the current segment.</P>
<P>The assembler will print an error message if the segment stack is already
full, when this command is issued.</P>
<P>See: <CODE>
<A HREF="#.POPSEG">.POPSEG</A></CODE></P>


<H2><A NAME=".REPEAT"></A> <A NAME="ss10.78">10.78</A> <A HREF="ca65.html#toc10.78"><CODE>.REPEAT</CODE></A>
</H2>


<P>Repeat all commands between <CODE>.REPEAT</CODE> and <CODE>
<A HREF="#.ENDREPEAT">.ENDREPEAT</A></CODE> constant number of times. The command is followed by
a constant expression that tells how many times the commands in the body
should get repeated. Optionally, a comma and an identifier may be specified.
If this identifier is found in the body of the repeat statement, it is
replaced by the current repeat count (starting with zero for the first time
the body is repeated).</P>
<P><CODE>.REPEAT</CODE> statements may be nested. If you use the same repeat count
identifier for a nested <CODE>.REPEAT</CODE> statement, the one from the inner
level will be used, not the one from the outer level.</P>
<P>Example:</P>
<P>The following macro will emit a string that is "encrypted" in that all
characters of the string are XORed by the value $55.</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .macro  Crypt   Arg
                .repeat .strlen(Arg), I
                .byte   .strat(Arg, I) .xor $55
                .endrep
        .endmacro
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.ENDREPEAT">.ENDREPEAT</A></CODE></P>


<H2><A NAME=".RELOC"></A> <A NAME="ss10.79">10.79</A> <A HREF="ca65.html#toc10.79"><CODE>.RELOC</CODE></A>
</H2>


<P>Switch back to relocatable mode. See the <CODE>
<A HREF="#.ORG">.ORG</A></CODE> command.</P>


<H2><A NAME=".RES"></A> <A NAME="ss10.80">10.80</A> <A HREF="ca65.html#toc10.80"><CODE>.RES</CODE></A>
</H2>


<P>Reserve storage. The command is followed by one or two constant
expressions. The first one is mandatory and defines, how many bytes of
storage should be defined. The second, optional expression must by a
constant byte value that will be used as value of the data. If there
is no fill value given, the linker will use the value defined in the
linker configuration file (default: zero).</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        ; Reserve 12 bytes of memory with value $AA
        .res    12, $AA
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".RODATA"></A> <A NAME="ss10.81">10.81</A> <A HREF="ca65.html#toc10.81"><CODE>.RODATA</CODE></A>
</H2>


<P>Switch to the RODATA segment. The name of the RODATA segment is always
"RODATA", so this is a shortcut for</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .segment  "RODATA"
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>The RODATA segment is a segment that is used by the compiler for
readonly data like string constants.</P>
<P>See also the <CODE>
<A HREF="#.SEGMENT">.SEGMENT</A></CODE> command.</P>


<H2><A NAME=".SCOPE"></A> <A NAME="ss10.82">10.82</A> <A HREF="ca65.html#toc10.82"><CODE>.SCOPE</CODE></A>
</H2>


<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
<A HREF="ca65-6.html#scopesyntax">explicit scope specification</A>. 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 <CODE>
<A HREF="#.ENDSCOPE">.ENDSCOPE</A></CODE> 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).</P>
<P>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.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .scope  Error                   ; Start new scope named Error
                None = 0                ; No error
                File = 1                ; File error
                Parse = 2               ; Parse error
        .endproc                        ; Close lexical level

                ...
                lda #Error::File        ; Use symbol from scope Error
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.ENDSCOPE">.ENDSCOPE</A></CODE> and <CODE>
<A HREF="#.PROC">.PROC</A></CODE></P>


<H2><A NAME=".SEGMENT"></A> <A NAME="ss10.83">10.83</A> <A HREF="ca65.html#toc10.83"><CODE>.SEGMENT</CODE></A>
</H2>


<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").</P>
<P>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 colon. Valid attributes are
"<CODE>zeropage</CODE>" and "<CODE>absolute</CODE>".</P>
<P>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.</P>
<P>"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.</P>
<P>Beware: Only labels in a segment with the zeropage attribute are marked
as reachable by short addressing. The `*' (PC counter) operator will
work as in other segments and will create absolute variable values.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .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
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.BSS">.BSS</A></CODE>, <CODE>
<A HREF="#.CODE">.CODE</A></CODE>, <CODE>
<A HREF="#.DATA">.DATA</A></CODE> and <CODE>
<A HREF="#.RODATA">.RODATA</A></CODE></P>


<H2><A NAME=".SETCPU"></A> <A NAME="ss10.84">10.84</A> <A HREF="ca65.html#toc10.84"><CODE>.SETCPU</CODE></A>
</H2>


<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 <CODE>
<A HREF="ca65-2.html#option--cpu">--cpu</A></CODE> 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".</P>
<P>See: <CODE>
<A HREF="ca65-8.html#.CPU">.CPU</A></CODE>,
<CODE>
<A HREF="#.IFP02">.IFP02</A></CODE>,
<CODE>
<A HREF="#.IFP816">.IFP816</A></CODE>,
<CODE>
<A HREF="#.IFPC02">.IFPC02</A></CODE>,
<CODE>
<A HREF="#.IFPSC02">.IFPSC02</A></CODE>,
<CODE>
<A HREF="#.P02">.P02</A></CODE>,
<CODE>
<A HREF="#.P816">.P816</A></CODE>,
<CODE>
<A HREF="#.PC02">.PC02</A></CODE>,
<CODE>
<A HREF="#.PSC02">.PSC02</A></CODE></P>


<H2><A NAME=".SMART"></A> <A NAME="ss10.85">10.85</A> <A HREF="ca65.html#toc10.85"><CODE>.SMART</CODE></A>
</H2>


<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.</P>
<P>In smart mode the assembler will do the following:</P>
<P>
<UL>
<LI>Track usage of the <CODE>REP</CODE> and <CODE>SEP</CODE> 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 <CODE>.Inn</CODE> and <CODE>.Ann</CODE>
instructions to tell the assembler about the current settings.</LI>
<LI>In 65816 mode, replace a <CODE>RTS</CODE> instruction by <CODE>RTL</CODE> if it is
used within a procedure declared as <CODE>far</CODE>, or if the procedure has
no explicit address specification, but it is <CODE>far</CODE> because of the
memory model used.</LI>
</UL>
</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .smart                          ; Be smart
        .smart  -                       ; Stop being smart
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.A16">.A16</A></CODE>,
<CODE>
<A HREF="#.A8">.A8</A></CODE>,
<CODE>
<A HREF="#.I16">.I16</A></CODE>,
<CODE>
<A HREF="#.I8">.I8</A></CODE></P>


<H2><A NAME=".STRUCT"></A> <A NAME="ss10.86">10.86</A> <A HREF="ca65.html#toc10.86"><CODE>.STRUCT</CODE></A>
</H2>


<P>Starts a struct definition. Structs are covered in a separate section named
<A HREF="ca65-13.html#structs">&quot;Structs and unions&quot;</A>.</P>
<P>See: <CODE>
<A HREF="#.ENDSTRUCT">.ENDSTRUCT</A></CODE></P>


<H2><A NAME=".SUNPLUS"></A> <A NAME="ss10.87">10.87</A> <A HREF="ca65.html#toc10.87"><CODE>.SUNPLUS</CODE></A>
</H2>


<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".</P>
<P>See: <CODE>
<A HREF="#.P02">.P02</A></CODE>, <CODE>
<A HREF="#.PSC02">.PSC02</A></CODE>, <CODE>
<A HREF="#.PC02">.PC02</A></CODE>, and
<CODE>
<A HREF="#.P816">.P816</A></CODE></P>


<H2><A NAME=".TAG"></A> <A NAME="ss10.88">10.88</A> <A HREF="ca65.html#toc10.88"><CODE>.TAG</CODE></A>
</H2>


<P>Allocate space for a struct or union.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .struct Point
                xcoord  .word
                ycoord  .word
        .endstruct

        .bss
                .tag    Point           ; Allocate 4 bytes
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".WARNING"></A> <A NAME="ss10.89">10.89</A> <A HREF="ca65.html#toc10.89"><CODE>.WARNING</CODE></A>
</H2>


<P>Force an assembly warning. The assembler will output a warning message
preceeded by "User warning". This warning will always be output, even if
other warnings are disabled with the <CODE>
<A HREF="ca65-2.html#option-W">-W0</A></CODE>
command line option.</P>
<P>This command may be used to output possible problems when assembling
the source file.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .macro  jne     target
                .local L1
                .ifndef target
                .warning "Forward jump in jne, cannot optimize!"
                beq     L1
                jmp     target
        L1:
                .else
                ...
                .endif
        .endmacro
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See also the <CODE>
<A HREF="#.ERROR">.ERROR</A></CODE> and <CODE>
<A HREF="#.OUT">.OUT</A></CODE> directives.</P>


<H2><A NAME=".WORD"></A> <A NAME="ss10.90">10.90</A> <A HREF="ca65.html#toc10.90"><CODE>.WORD</CODE></A>
</H2>


<P>Define word sized data. Must be followed by a sequence of (word ranged,
but not necessarily constant) expressions.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .word   $0D00, $AF13, _Clear
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".ZEROPAGE"></A> <A NAME="ss10.91">10.91</A> <A HREF="ca65.html#toc10.91"><CODE>.ZEROPAGE</CODE></A>
</H2>


<P>Switch to the ZEROPAGE segment and mark it as direct (zeropage) segment.
The name of the ZEROPAGE segment is always "ZEROPAGE", so this is a
shortcut for</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .segment  "ZEROPAGE": zeropage
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Because of the "zeropage" attribute, labels declared in this segment are
addressed using direct addressing mode if possible. You <EM>must</EM> instruct
the linker to place this segment somewhere in the address range 0..$FF
otherwise you will get errors.</P>
<P>See: <CODE>
<A HREF="#.SEGMENT">.SEGMENT</A></CODE></P>



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