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Re: GCC 3.1 Issues
Richard Henderson <rth@redhat.com> writes:
> On Tue, Mar 12, 2002 at 07:13:10AM +0100, Andreas Jaeger wrote:
>> -If your assembler instruction modifies memory in an unpredictable
>> +If your assembler instruction access memory in an unpredictable
>> fashion, add @samp{memory} to the list of clobbered registers.
>
> *shrug* If you have some concept of how large the memory you
> are accessing, you can also add it as an input.
How can I add this as input, it let's say I want to access ten bytes
of a string?
For now I've changed the paragraph to:
If your assembler instructions access memory in an unpredictable
fashion, add @samp{memory} to the list of clobbered registers. This
will cause GCC to not keep memory values cached in registers across
the assembler instruction. You will also want to add the
@code{volatile} keyword if the memory affected is not listed in the
inputs or outputs of the @code{asm}, as the @samp{memory} clobber does
not count as a side-effect of the @code{asm}. If you known how large the
accessed memory is, you can add it as input or output but if this is not
known, you should add @samp{memory}.
Further improvements are welcome,
Andreas
--
Andreas Jaeger
SuSE Labs aj@suse.de
private aj@arthur.inka.de
http://www.suse.de/~aj