lkml.org 
[lkml]   [2018]   [Jan]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 2/8] x86/entry/clearregs: Add infrastructure to clear registers
> > +	.macro CLEAR_ALL_REGS
> > + CLEAR_R8_TO_R15
> > + xorl %eax, %eax
> > + xorl %ebx, %ebx
>
> How come you use xorl vs xorq?

64bit always zero extends 32->64, and xorl is one byte
shorter because it doesn't need a REX prefix.

-Andi

\
 
 \ /
  Last update: 2018-01-14 23:24    [W:0.093 / U:0.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site