lkml.org 
[lkml]   [2008]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 13/17] Immediate Values - x86 Optimization (updated)
Mathieu Desnoyers wrote:
>
> Hrm, since even the nmi-safe version supports REX-prefixed instructions,
> there is no need for an =q constraint on single-byte immediate values
> anymore. (thanks to your "discard" section used in the nmi-safe version)
>

WRONG!

Using =r for single-byte values is incorrect for 32-bit code -- that
would permit %spl, %bpl, %sil, %dil which are illegal in 32-bit mode.
That is not the incorrect bit, it's the description that is confused.

-hpa


\
 
 \ /
  Last update: 2008-04-10 00:51    [W:0.061 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site