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Re: inline asm and status flags on x86
On Thu, May 04, 2000 at 01:42:31PM -0400, Geoff Berry wrote:
> How's this?
>
> 2000-05-04 Geoff Berry <geoffb@bops.com>
>
> * extend.texi (Extended Asm): Document inability to give asm
> statements access to condition codes.
>
> Index: extend.texi
> ===================================================================
> RCS file: /cvs/gcc/egcs/gcc/extend.texi,v
> retrieving revision 1.44
> diff -c -3 -p -r1.44 extend.texi
> *** extend.texi 2000/03/14 08:24:21 1.44
> --- extend.texi 2000/05/04 17:39:52
> *************** instructions would alter the condition c
> *** 2662,2667 ****
> --- 2662,2671 ----
> test it. This problem doesn't arise for ordinary ``test'' and
> ``compare'' instructions because they don't have any output operands.
>
> + For reasons similar to those described above, it is not possible to give
> + an assembler instruction access to the condition code left by previous
> + instructions.
> +
> If you are writing a header file that should be includable in ANSI C
> programs, write @code{__asm__} instead of @code{asm}. @xref{Alternate
> Keywords}.
We probably should at least think about redoing the wording of previous
paragraph for non-CC0 machines.
--
Michael Meissner, Cygnus Solutions, a Red Hat company.
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