Re: i386/x86_64 segment register issuses (Re: PATCH: Fix x86 segmentregister access)

From: Pau Aliagas
Date: Wed Mar 30 2005 - 17:20:09 EST


On Wed, 30 Mar 2005, H. J. Lu wrote:

On Wed, Mar 30, 2005 at 07:57:28AM -0800, Linus Torvalds wrote:

There is no such an instruction of "movl %ds,(%eax)". The old assembler
accepts it and turns it into "movw %ds,(%eax)".

I disagree. Violently. As does the old assembler, which does not turn
"mov" into "movw" as you say. AT ALL.

I should have made myself clear. By "movw %ds,(%eax)", I meant:

8c 18 movw %ds,(%eax)

That is what the assembler generates, and should have generated, for
"movw %ds,(%eax)" since Nov. 4, 2004.

Could this be the reason for the reported slowdown in the last six months?

--

Pau
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