Re: NOP instruction

Horst von Brand (vonbrand@inf.utfsm.cl)
Wed, 16 Dec 1998 15:57:24 -0300


Chris Wedgwood <chris@cybernet.co.nz> said:
> On Wed, Dec 16, 1998 at 11:36:00AM +1030, Mofeed Shahin wrote:
> > Ummm, I was under the impression that NOP under the intel was 0x90...

> nope

> > I am pretty sure the intel does have a real NOP.

[...]

> As you can see -- gas treats nop as xchg %eax,%eax.

What difference does it make that for ia32 "xchg %eax,%eax" has no effect
and is a byte long, so it's a perfect excuse for intel to call it "nop" and
treat it as such (and even optimize the Si so it _really_ doesn't do
anything at all). Why on earth should they then go out of their way to
declare, say, 0x00 as nop?

Can we _please_ drop this useless discussion? It's not even religious...

-- 
Dr. Horst H. von Brand                       mailto:vonbrand@inf.utfsm.cl
Departamento de Informatica                     Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria              +56 32 654239
Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513

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