Optimized gcc function calling assembler.

[Dave Pitts]

Hello:

I've been working with a third party supplied assembler function that seems to
have issues when being called from optimized gcc code. I get spurious values in
calling function. It appears that the assembler function is using registers that
the gcc code is expecting to not change. Is there a way, in gcc, to protect
against the assembler function from doing immoral acts.... The system is an
x86_64 based Linux system. I don't know the assembler language for this system
very well.

Thanks in advance....

--
Dave Pitts PULLMAN: Travel and sleep in safety and comfort.
dpi...@cozx.com

[Andrew Haley]

Dave Pitts <dpi...@cozx.com> wrote:

> I've been working with a third party supplied assembler function
> that seems to have issues when being called from optimized gcc
> code. I get spurious values in calling function. It appears that the
> assembler function is using registers that the gcc code is expecting
> to not change.

Oops.

> Is there a way, in gcc, to protect against the assembler function
> from doing immoral acts.... The system is an x86_64 based Linux
> system. I don't know the assembler language for this system very
> well.

Sure, you just have to save and restore the registers; it's not hard.
We can't tell you any more without specifics.

Andrew.