Re: [PATCH] 2.1.131: i386 tweak to switch_to()

Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
Tue, 15 Dec 1998 17:22:02 +0100 (CET)

On Tue, 15 Dec 1998, Andrea Arcangeli wrote:
> On Tue, 15 Dec 1998, Geert Uytterhoeven wrote:
>
> >cc == condition codes
>
> Ah, but does gcc have a way to save/restore the condition code register
> on i386? (and btw the condition code register is eflags? right?)

I don't know that much about ia32 assembler. I don't have any ia32 boxes.

But you use the `cc' constraint to tell gcc that the inline asm may have
changed the condition codes. Some instructions don't change cc, others do. On
PPC, you can even decide yourself whether you want an instruction to influence
the cc or not.

Greetings,

Geert

--
Geert Uytterhoeven                     Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP}  http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium




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