6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2024-06-02 04:41:35 +00:00
Code Issues Projects Releases Wiki Activity

Updated documentation on string literal translation in asm() and _Static_assert().

Browse Source
This commit is contained in:
acqn 2023-10-15 16:43:40 +08:00
parent 7b0d1d9679
commit 21b6cbb66e
1 changed files with 28 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
doc/cc65.sgml
View File

@ -837,21 +837,21 @@ This cc65 version has some extensions to the ISO C standard.
<itemize> <itemize>
<item> The compiler allows to insert assembler expressions into the output <item> The compiler allows to insert inline assembler code in the form of the
file. The syntax is <tt/asm/ expression into the output file. The syntax is
<tscreen><verb> <tscreen><verb>
asm [optional volatile] (&lt;string literal&gt;[, optional parameters]) ; asm [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen> </verb></tscreen>
or or
<tscreen><verb> <tscreen><verb>
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters]) ; __asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen> </verb></tscreen>
The first form is in the user namespace; and, is disabled if the <tt/-A/ The first form is in the user namespace; and, is disabled if the <tt/-A/
switch is given. switch is given.
There is a whole section covering inline assembler expressions, There is a whole section covering the inline assembler,
<ref id="inline-asm" name="see there">. <ref id="inline-asm" name="see there">.
<p> <p>
@ -1008,6 +1008,13 @@ This cc65 version has some extensions to the ISO C standard.
<tt/_Static_assert/ is also available as the macro <tt/static_assert/ in <tt/_Static_assert/ is also available as the macro <tt/static_assert/ in
<tt/assert.h/. <tt/assert.h/.
Note: The string literal as the message in the <tt/_Static_assert/
declaration is not subject to string literal translation (see
<tt/<ref id="pragma-charmap" name="#pragma&nbsp;charmap()">/) and will
always be in the host encoding. On the other hand, any character or
string literals present in the condition expression of the
<tt/_Static_assert/ declaration will be translated as usual.
<item> cc65 supports bit-fields of any integral type that is int-sized or <item> cc65 supports bit-fields of any integral type that is int-sized or
smaller, and enumerated types with those types as their underlying smaller, and enumerated types with those types as their underlying
type. (Only <tt/int/, <tt/signed int/, and <tt/unsigned int/ are type. (Only <tt/int/, <tt/signed int/, and <tt/unsigned int/ are
@ -1317,7 +1324,9 @@ parameter with the <tt/#pragma/.
<sect1><tt>#pragma charmap (&lt;index&gt;, &lt;code&gt;)</tt><label id="pragma-charmap"><p> <sect1><tt>#pragma charmap (&lt;index&gt;, &lt;code&gt;)</tt><label id="pragma-charmap"><p>
Each literal string and each literal character in the source is translated Each literal string and each literal character in the preprocessed source,
except when used in an <tt/asm/ expression as the inline assembler code or
in a <tt/_Static_assert/ declaration as the failure message, is translated
by use of a translation table. That translation table is preset when the by use of a translation table. That translation table is preset when the
compiler is started, depending on the target system; for example, to map compiler is started, depending on the target system; for example, to map
ISO-8859-1 characters into PETSCII if the target is a Commodore machine. ISO-8859-1 characters into PETSCII if the target is a Commodore machine.
@ -1714,23 +1723,23 @@ bloated code and a slowdown.
<sect>Inline assembler<label id="inline-asm"><p> <sect>Inline assembler<label id="inline-asm"><p>
The compiler allows to insert assembler expressions into the output file. The The compiler allows to insert inline assembler code in the form of the <tt/asm/
syntax is expression into the output file. The syntax is
<tscreen><verb> <tscreen><verb>
asm [optional volatile] (&lt;string literal&gt;[, optional parameters]) ; asm [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen> </verb></tscreen>
or or
<tscreen><verb> <tscreen><verb>
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters]) ; __asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen> </verb></tscreen>
<p> <p>
The first form is in the user namespace; and, is disabled by <tt><ref The first form is in the user namespace; and, is disabled by <tt><ref
id="option--standard" name="--standard"></tt> if the argument is not <tt/cc65/. id="option--standard" name="--standard"></tt> if the argument is not <tt/cc65/.
The <tt/asm/ expression can be used only inside a function. Please note that The <tt/asm/ expression can be used only inside a function. The result of an
the result of an inline assembler expression is always of type <tt/void/. <tt/asm/ expression is always of type <tt/void/.
The contents of the string literal are preparsed by the compiler; and, inserted The contents of the string literal are preparsed by the compiler; and, inserted
into the generated assembly output, so that it can be processed further by into the generated assembly output, so that it can be processed further by
@ -1757,6 +1766,13 @@ The string literal may contain format specifiers from the following list. For
each format specifier, an argument is expected which is inserted instead of each format specifier, an argument is expected which is inserted instead of
the format specifier, before passing the assembly code line to the backend. the format specifier, before passing the assembly code line to the backend.
Note: The string literal as the inline assembler code itself in the <tt/asm/
expression is not subject to string literal translation (see
<tt/<ref id="pragma-charmap" name="#pragma&nbsp;charmap()">/) and will always
be in the host encoding. On the other hand, all character and string literals
as the arguments for replacing the format specifiers will be translated as
usual.
<itemize> <itemize>
<item><tt/%b/ - Numerical 8-bit value <item><tt/%b/ - Numerical 8-bit value
<item><tt/%w/ - Numerical 16-bit value <item><tt/%w/ - Numerical 16-bit value