ca65-10.html

cc65 的编译器文档

<DT><B><CODE>dollar_in_identifiers</CODE></B><DD><P>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.</P>

<DT><B><CODE>leading_dot_in_identifiers</CODE></B><DD><P>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.</P>

<DT><B><CODE>pc_assignment</CODE></B><DD><P>Allow assignments to the PC symbol (`*' or `$' if <CODE>dollar_is_pc</CODE>
is enabled). Such an assignment is handled identical to the <CODE>
<A HREF="#.ORG">.ORG</A></CODE> 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).</P>

</DL>
</P>
<P>It is also possible to specify features on the command line using the
<CODE>
<A HREF="ca65-2.html#option--feature">--feature</A></CODE> command line option.
This is useful when translating sources written for older assemblers, when
you don't want to change the source code.</P>
<P>As an example, to translate sources written for Andre Fachats xa65
assembler, the features</P>
<P>
<PRE>
        labels_without_colons, pc_assignment, loose_char_term
  
</PRE>
</P>
<P>may be helpful. They do not make ca65 completely compatible, so you may not
be able to translate the sources without changes, even when enabling these
features. However, I have found several sources that translate without
problems when enabling these features on the command line.</P>


<H2><A NAME=".FOPT"></A> <A NAME="ss10.39">10.39</A> <A HREF="ca65.html#toc10.39"><CODE>.FILEOPT, .FOPT</CODE></A>
</H2>


<P>Insert an option string into the object file. There are two forms of
this command, one specifies the option by a keyword, the second
specifies it as a number. Since usage of the second one needs knowledge
of the internal encoding, its use is not recommended and I will only
describe the first form here.</P>
<P>The command is followed by one of the keywords</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        author
        comment
        compiler
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>a comma and a string. The option is written into the object file
together with the string value. This is currently unidirectional and
there is no way to actually use these options once they are in the
object file.</P>
<P>Examples:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .fileopt        comment, "Code stolen from my brother"
        .fileopt        compiler, "BASIC 2.0"
        .fopt           author, "J. R. User"
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".FORCEIMPORT"></A> <A NAME="ss10.40">10.40</A> <A HREF="ca65.html#toc10.40"><CODE>.FORCEIMPORT</CODE></A>
</H2>


<P>Import an absolute symbol from another module. The command is followed by a
comma separated list of symbols to import. The command is similar to <CODE>
<A HREF="#.IMPORT">.IMPORT</A></CODE>, but the import reference is always
written to the generated object file, even if the symbol is never referenced
(<CODE>
<A HREF="#.IMPORT">.IMPORT</A></CODE> will not generate import
references for unused symbols).</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .forceimport    needthisone, needthistoo
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.IMPORT">.IMPORT</A></CODE></P>


<H2><A NAME=".GLOBAL"></A> <A NAME="ss10.41">10.41</A> <A HREF="ca65.html#toc10.41"><CODE>.GLOBAL</CODE></A>
</H2>


<P>Declare symbols as global. Must be followed by a comma separated list of
symbols to declare. Symbols from the list, that are defined somewhere in the
source, are exported, all others are imported. Additional <CODE>
<A HREF="#.IMPORT">.IMPORT</A></CODE> or <CODE>
<A HREF="#.EXPORT">.EXPORT</A></CODE> commands for the same symbol are allowed.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .global foo, bar
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".GLOBALZP"></A> <A NAME="ss10.42">10.42</A> <A HREF="ca65.html#toc10.42"><CODE>.GLOBALZP</CODE></A>
</H2>


<P>Declare symbols as global. Must be followed by a comma separated list of
symbols to declare. Symbols from the list, that are defined somewhere in the
source, are exported, all others are imported. Additional <CODE>
<A HREF="#.IMPORTZP">.IMPORTZP</A></CODE> or <CODE>
<A HREF="#.EXPORTZP">.EXPORTZP</A></CODE> commands for the same symbol are allowed. The symbols
in the list are explicitly marked as zero page symols.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .globalzp foo, bar
  
</PRE>
</CODE></BLOCKQUOTE>
</P>


<H2><A NAME=".I16"></A> <A NAME="ss10.43">10.43</A> <A HREF="ca65.html#toc10.43"><CODE>.I16</CODE></A>
</H2>


<P>Valid only in 65816 mode. Switch the index registers to 16 bit.</P>
<P>Note: This command will not emit any code, it will tell the assembler to
create 16 bit operands for immediate operands.</P>
<P>See also the <CODE>
<A HREF="#.I8">.I8</A></CODE> and <CODE>
<A HREF="#.SMART">.SMART</A></CODE> commands.</P>


<H2><A NAME=".I8"></A> <A NAME="ss10.44">10.44</A> <A HREF="ca65.html#toc10.44"><CODE>.I8</CODE></A>
</H2>


<P>Valid only in 65816 mode. Switch the index registers to 8 bit.</P>
<P>Note: This command will not emit any code, it will tell the assembler to
create 8 bit operands for immediate operands.</P>
<P>See also the <CODE>
<A HREF="#.I16">.I16</A></CODE> and <CODE>
<A HREF="#.SMART">.SMART</A></CODE> commands.</P>


<H2><A NAME=".IF"></A> <A NAME="ss10.45">10.45</A> <A HREF="ca65.html#toc10.45"><CODE>.IF</CODE></A>
</H2>


<P>Conditional assembly: Evalute 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.</P>
<P>A expression value of zero evaluates to FALSE, any other value evaluates
to TRUE.</P>


<H2><A NAME=".IFBLANK"></A> <A NAME="ss10.46">10.46</A> <A HREF="ca65.html#toc10.46"><CODE>.IFBLANK</CODE></A>
</H2>


<P>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 <CODE>
<A HREF="#.ELSE">.ESLE</A></CODE>, <CODE>
<A HREF="#.ELSEIF">.ELSEIF</A></CODE> or
<CODE>
<A HREF="#.ENDIF">.ENDIF</A></CODE> directive.</P>
<P>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.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .macro     arg1, arg2
        .ifblank   arg2
                   lda     #arg1
        .else
                   lda     #arg2
        .endif
        .endmacro
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See also: <CODE>
<A HREF="ca65-9.html#.BLANK">.BLANK</A></CODE></P>


<H2><A NAME=".IFCONST"></A> <A NAME="ss10.47">10.47</A> <A HREF="ca65.html#toc10.47"><CODE>.IFCONST</CODE></A>
</H2>


<P>Conditional assembly: Evaluate an expression and switch assembler output
on or off depending on the constness of the expression.</P>
<P>A const expression evaluates to to TRUE, a non const expression (one
containing an imported or currently undefined symbol) evaluates to
FALSE.</P>
<P>See also: <CODE>
<A HREF="ca65-9.html#.CONST">.CONST</A></CODE></P>


<H2><A NAME=".IFDEF"></A> <A NAME="ss10.48">10.48</A> <A HREF="ca65.html#toc10.48"><CODE>.IFDEF</CODE></A>
</H2>


<P>Conditional assembly: Check if a symbol is defined. Must be followed by
a symbol name. The condition is true if the the given symbol is already
defined, and false otherwise.</P>
<P>See also: <CODE>
<A HREF="#.DEFINED">.DEFINED</A></CODE></P>


<H2><A NAME=".IFNBLANK"></A> <A NAME="ss10.49">10.49</A> <A HREF="ca65.html#toc10.49"><CODE>.IFNBLANK</CODE></A>
</H2>


<P>Conditional assembly: Check if there are any remaining tokens in this line,
and evaluate to TRUE if this is the case, and to FALSE otherwise. If the
condition is not true, further lines are not assembled until an <CODE>
<A HREF="#.ELSE">.ELSE</A></CODE>, <CODE>
<A HREF="#.ELSEIF">.ELSEIF</A></CODE> or
<CODE>
<A HREF="#.ENDIF">.ENDIF</A></CODE> directive.</P>
<P>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.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .macro     arg1, arg2
                   lda     #arg1
        .ifnblank  arg2
                   lda     #arg2
        .endif
        .endmacro
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See also: <CODE>
<A HREF="ca65-9.html#.BLANK">.BLANK</A></CODE></P>


<H2><A NAME=".IFNDEF"></A> <A NAME="ss10.50">10.50</A> <A HREF="ca65.html#toc10.50"><CODE>.IFNDEF</CODE></A>
</H2>


<P>Conditional assembly: Check if a symbol is defined. Must be followed by
a symbol name. The condition is true if the the given symbol is not
defined, and false otherwise.</P>
<P>See also: <CODE>
<A HREF="#.DEFINED">.DEFINED</A></CODE></P>


<H2><A NAME=".IFNREF"></A> <A NAME="ss10.51">10.51</A> <A HREF="ca65.html#toc10.51"><CODE>.IFNREF</CODE></A>
</H2>


<P>Conditional assembly: Check if a symbol is referenced. Must be followed
by a symbol name. The condition is true if if the the given symbol was
not referenced before, and false otherwise.</P>
<P>See also: <CODE>
<A HREF="ca65-9.html#.REFERENCED">.REFERENCED</A></CODE></P>


<H2><A NAME=".IFP02"></A> <A NAME="ss10.52">10.52</A> <A HREF="ca65.html#toc10.52"><CODE>.IFP02</CODE></A>
</H2>


<P>Conditional assembly: Check if the assembler is currently in 6502 mode
(see <CODE>
<A HREF="#.P02">.P02</A></CODE> command).</P>


<H2><A NAME=".IFP816"></A> <A NAME="ss10.53">10.53</A> <A HREF="ca65.html#toc10.53"><CODE>.IFP816</CODE></A>
</H2>


<P>Conditional assembly: Check if the assembler is currently in 65816 mode
(see <CODE>
<A HREF="#.P816">.P816</A></CODE> command).</P>


<H2><A NAME=".IFPC02"></A> <A NAME="ss10.54">10.54</A> <A HREF="ca65.html#toc10.54"><CODE>.IFPC02</CODE></A>
</H2>


<P>Conditional assembly: Check if the assembler is currently in 65C02 mode
(see <CODE>
<A HREF="#.PC02">.PC02</A></CODE> command).</P>


<H2><A NAME=".IFPSC02"></A> <A NAME="ss10.55">10.55</A> <A HREF="ca65.html#toc10.55"><CODE>.IFPSC02</CODE></A>
</H2>


<P>Conditional assembly: Check if the assembler is currently in 65SC02 mode
(see <CODE>
<A HREF="#.PSC02">.PSC02</A></CODE> command).</P>


<H2><A NAME=".IFREF"></A> <A NAME="ss10.56">10.56</A> <A HREF="ca65.html#toc10.56"><CODE>.IFREF</CODE></A>
</H2>


<P>Conditional assembly: Check if a symbol is referenced. Must be followed
by a symbol name. The condition is true if if the the given symbol was
referenced before, and false otherwise.</P>
<P>This command may be used to build subroutine libraries in include files
(you may use separate object modules for this purpose too).</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .ifref  ToHex                   ; If someone used this subroutine
        ToHex:  tay                     ; Define subroutine
                lda     HexTab,y
                rts
        .endif
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See also: <CODE>
<A HREF="ca65-9.html#.REFERENCED">.REFERENCED</A></CODE></P>


<H2><A NAME=".IMPORT"></A> <A NAME="ss10.57">10.57</A> <A HREF="ca65.html#toc10.57"><CODE>.IMPORT</CODE></A>
</H2>


<P>Import a symbol from another module. The command is followed by a comma
separated list of symbols to import, with each one optionally followed by
an address specification.</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .import foo
        .import bar: zeropage
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.IMPORTZP">.IMPORTZP</A></CODE></P>


<H2><A NAME=".IMPORTZP"></A> <A NAME="ss10.58">10.58</A> <A HREF="ca65.html#toc10.58"><CODE>.IMPORTZP</CODE></A>
</H2>


<P>Import a symbol from another module. The command is followed by a comma
separated list of symbols to import. The symbols are explicitly imported
as zero page symbols (that is, symbols with values in byte range).</P>
<P>Example:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
        .importzp       foo, bar
  
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>See: <CODE>
<A HREF="#.IMPORT">.IMPORT</A></CODE></P>