Effect of additionnal save/restore instructions

Gedare Bloom gedare at rtems.org
Tue Apr 30 12:30:37 UTC 2013


Ah, my example is missing a colon. you want something like
__asm__ __volatile__("dec 1, %%o0\n\t" : : : "o0");

I guess my gmail asm syntax checker was broken!
-Gedare

On Tue, Apr 30, 2013 at 2:17 AM, Leonard Bise <leonard.bise at syderal.ch> wrote:
> Thank you for the explanation.
> I finally found out about the ABI of the SPARC v8 and some explanation here
> : http://www.sics.se/~psm/sparcstack.html
>
> It says clearly that the local register are "assumed by caller to be
> preserved across a procedure call", which would imply that I cannot modify
> it like this without turning the window. And then it makes sense that the
> output or global register can be safely used.
>
> Before we were happily breaching the ABI! Shame on us.
>
> Another small question, Gedare posted an example using the o0 register and
> adding it in the clobber list. However when trying to compile there is an
> error. Seem like I cannot have only a clobbered register without at least
> one input or output, is this as expected or should I be able to add only a
> clobber list?
>
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