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From: "Rod Pemberton" <do_not_have AT nohavenot DOT cmm>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Using inline asm
Date: Wed, 24 Oct 2007 22:52:23 -0400
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To: djgpp AT delorie DOT com
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"DJ Delorie" <dj AT delorie DOT com> wrote in message
news:200710250120 DOT l9P1KEb2032374 AT envy DOT delorie DOT com...
>
> >    int iRet;
> >    asm ("cpuid");
> >    asm ("movl %eax,%0" : "=g" (iRet));
>
> Should be %%eax
>
> This might work better (because know gcc will know that eax is
> clobbered):
>
> >    asm ("cpuid" : "=a" (iRet));

Huh?  I'm sure I missed something...  That takes care of eax for cpuid, but
that ignores ebx, ecx, and edx.  cpuid trashes those four registers whether
he returns them or not, correct?   How does GCC correct the other three?


Rod Pemberton