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[PATCH] x86_64: prefetchw() can fall back to prefetch() if !3DNOW

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This is a multi-part message in MIME format.  If the cpu lacks 3DNOW
feature, we can use a normal prefetcht0 instruction instead of NOP5.
"prefetchw (%rxx)" and "prefetcht0 (%rxx)" have the same length, ranging
from 3 to 5 bytes depending on the register.  So this patch even helps
AMD64, shortening the length of the code.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Eric Dumazet 2005-09-06 15:16:17 -07:00 committed by Linus Torvalds
parent c078d3266e
commit 19aaabb584
1 changed files with 1 additions and 1 deletions
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2
include/asm-x86_64/processor.h
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@ -398,7 +398,7 @@ static inline void prefetch(void *x)
#define ARCH_HAS_PREFETCHW 1
static inline void prefetchw(void *x)
{
alternative_input(ASM_NOP5,
alternative_input("prefetcht0 (%1)",
"prefetchw (%1)",
X86_FEATURE_3DNOW,
"r" (x));