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

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acqn 2023-10-15 16:43:40 +08:00
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commit 21b6cbb66e
1 changed files with 28 additions and 12 deletions
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doc/cc65.sgml
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@ -837,21 +837,21 @@ This cc65 version has some extensions to the ISO C standard.
<itemize>
<item> The compiler allows to insert assembler expressions into the output
file. The syntax is
<item> The compiler allows to insert inline assembler code in the form of the
<tt/asm/ expression into the output file. The syntax is
<tscreen><verb>
asm [optional volatile] (&lt;string literal&gt;[, optional parameters]) ;
asm [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen>
or
<tscreen><verb>
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters]) ;
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen>
The first form is in the user namespace; and, is disabled if the <tt/-A/
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">.
<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/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
smaller, and enumerated types with those types as their underlying
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>
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
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.
@ -1714,23 +1723,23 @@ bloated code and a slowdown.
<sect>Inline assembler<label id="inline-asm"><p>
The compiler allows to insert assembler expressions into the output file. The
syntax is
The compiler allows to insert inline assembler code in the form of the <tt/asm/
expression into the output file. The syntax is
<tscreen><verb>
asm [optional volatile] (&lt;string literal&gt;[, optional parameters]) ;
asm [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen>
or
<tscreen><verb>
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters]) ;
__asm__ [optional volatile] (&lt;string literal&gt;[, optional parameters])
</verb></tscreen>
<p>
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/.
The <tt/asm/ expression can be used only inside a function. Please note that
the result of an inline assembler expression is always of type <tt/void/.
The <tt/asm/ expression can be used only inside a function. The result of an
<tt/asm/ expression is always of type <tt/void/.
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
@ -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
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>
<item><tt/%b/ - Numerical 8-bit value
<item><tt/%w/ - Numerical 16-bit value