lkml.org 
[lkml]   [1996]   [May]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Is clobber "memory" in include/asm-i386/system.h necessary?
On Thu, 2 May 1996, Alan Cox wrote:

> > So what's up with these clobbers? If they aren't necessary, they
> > should be removed because they have a detrimental effect on code
> > generation. If they are necessary, how about a comment explaining
> > why?
>
> To force a cli/sti to act as a store/load barrier. That saves all the variables
> in the interrupt code being volatile and making gcc generate diabolically
> bad code.
>
> Alan
>

Rember Tom, as Linus has often said, the whole idea it to trick gcc into
producing better code (that's why there are goto's all over some source
files, where other clauses would read much better, a switch for instance).

>
Bryn
--
PGP key pass phrase forgotten, \ Overload -- core meltdown sequence
again :( | initiated.
/ This space is intentionally left
| blank, apart from this text ;-)
\____________________________________



\
 
 \ /
  Last update: 2005-03-22 13:37    [W:0.057 / U:6.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site