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Re: Feature request: ability to describe x86 register halves as contraints.
- To: ak at muc dot de
- Subject: Re: Feature request: ability to describe x86 register halves as contraints.
- From: Alan Modra <alan at spri dot levels dot unisa dot edu dot au>
- Date: Wed, 1 Jul 1998 10:14:02 +0930 (CST)
- cc: egcs at cygnus dot com
On Tue, 30 Jun 1998 ak@muc.de wrote:
> > asm ("# %0 %b0 %h0 %w0 %k0" : : "q"(x));
> >
> > yields
> >
> > # %eax %al %ah %ax %eax
>
> Ok, I feel stupid now, but to my defense I must say that this is not
> documented in the info pages.
Yes, you have to dig into i386.md
Colin Plumb <colin@nyx.net> wrote a really good, tutorial style,
description of x86 constraints. If you ask him, I guess he'd be happy to
send it to you. His tutorial really ought to be part of egcs
documentation.