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Document the new #pragma syntax. Add comment about not using the asm names

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of global symbols in inline assembler statements.


git-svn-id: svn://svn.cc65.org/cc65/trunk@1460 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2002-10-10 21:44:19 +00:00
parent ab4a9eb5db
commit c3661446ee
1 changed files with 31 additions and 20 deletions
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51
doc/cc65.sgml
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@ -615,13 +615,13 @@ generation and other stuff.
<itemize> <itemize>
<item>The character index is actually the code of the character in the <item>The character index is actually the code of the character in the
C source, so character mappings do always depend on the source C source, so character mappings do always depend on the source
character set. This means that <tt/#pragma charmap/ is not portable character set. This means that <tt/#pragma charmap/ is not portable
- it depends on the build environment. - it depends on the build environment.
<item>While it is possible to use character literals as indices, the <item>While it is possible to use character literals as indices, the
result may be somewhat unexpected, since character literals are result may be somewhat unexpected, since character literals are
itself translated. For this reason I would suggest to avoid itself translated. For this reason I would suggest to avoid
character literals and use numeric character codes instead. character literals and use numeric character codes instead.
</itemize> </itemize>
Example: Example:
@ -631,7 +631,7 @@ generation and other stuff.
</verb></tscreen> </verb></tscreen>
<sect1><tt>#pragma checkstack (&lt;const int&gt;)</tt><label <sect1><tt>#pragma checkstack (on|off)</tt><label
id="pragma-checkstack"><p> id="pragma-checkstack"><p>
Tells the compiler to insert calls to a stack checking subroutine to detect Tells the compiler to insert calls to a stack checking subroutine to detect
@ -640,7 +640,7 @@ id="pragma-checkstack"><p>
program and switch it off for the release version. If a stack overflow is program and switch it off for the release version. If a stack overflow is
detected, the program is aborted. detected, the program is aborted.
If the argument is zero, stack checks are disabled (the default), otherwise If the argument is "off", stack checks are disabled (the default), otherwise
they're enabled. they're enabled.
@ -692,12 +692,12 @@ id="pragma-checkstack"><p>
</verb></tscreen> </verb></tscreen>
<sect1><tt>#pragma regvaraddr (&lt;const int&gt;)</tt><p> <sect1><tt>#pragma regvaraddr (on|off)</tt><p>
The compiler does not allow to take the address of register variables. The compiler does not allow to take the address of register variables.
The regvaraddr pragma changes this. Taking the address of a register The regvaraddr pragma changes this. Taking the address of a register
variable is allowed after using this pragma, if the argument is not variable is allowed after using this pragma with "on" as argument.
zero. Using an argument of zero changes back to the default behaviour. Using "off" as an argument switches back to the default behaviour.
Beware: The C standard does not allow taking the address of a variable Beware: The C standard does not allow taking the address of a variable
declared as register. So your programs become non-portable if you use declared as register. So your programs become non-portable if you use
@ -714,22 +714,21 @@ id="pragma-checkstack"><p>
</verb></tscreen> </verb></tscreen>
<sect1><tt>#pragma signedchars (&lt;const int&gt;)</tt><label <sect1><tt>#pragma signedchars (on|off)</tt><label id="pragma-signedchars"><p>
id="pragma-signedchars"><p>
Changes the signedness of the default character type. If the argument Changes the signedness of the default character type. If the argument is
is not zero, default characters are signed, otherwise characters are "on", default characters are signed, otherwise characters are unsigned.
unsigned. The compiler default is to make characters unsigned since this The compiler default is to make characters unsigned since this creates a
creates a lot better code. This default may be overridden by the lot better code. This default may be overridden by the <tt/--signed-chars/
<tt/--signed-chars/ command line option. command line option.
<sect1><tt>#pragma staticlocals (&lt;const int&gt;)</tt><label <sect1><tt>#pragma staticlocals (on|off)</tt><label
id="pragma-staticlocals"<p> id="pragma-staticlocals"<p>
Use variables in the bss segment instead of variables on the stack. This Use variables in the bss segment instead of variables on the stack. This
pragma changes the default set by the compiler option <tt/-Cl/. If the pragma changes the default set by the compiler option <tt/-Cl/. If the
argument is not zero, local variables are allocated in the BSS segment, argument is "on", local variables are allocated in the BSS segment,
leading to shorter and in most cases faster, but non-reentrant code. leading to shorter and in most cases faster, but non-reentrant code.
@ -820,6 +819,18 @@ Or, to access a struct member of a static variable:
</verb></tscreen> </verb></tscreen>
<p> <p>
Note: Do not embedd the assembler labels that are used as names of global
variables into your asm statements. Code like this
<tscreen><verb>
int foo;
__asm__ ("lda _foo"); /* DON'T DO THAT! */
</verb></tscreen>
<p>
may stop working if the way, the compiler generates variable names is changed
in a future version.
<p>
<sect>Bugs/Feedback<p> <sect>Bugs/Feedback<p>