The patch titled
i386 memcpy: minor optimization
has been added to the -mm tree. Its filename is
i386-memcpy-minor-optimization.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: i386 memcpy: minor optimization
From: Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx>
Skip an additional instruction if memcpy size is divisible by four.
Signed-off-by: Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-i386/string.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff -puN include/asm-i386/string.h~i386-memcpy-minor-optimization include/asm-i386/string.h
--- devel/include/asm-i386/string.h~i386-memcpy-minor-optimization 2006-05-30 18:15:33.000000000 -0700
+++ devel-akpm/include/asm-i386/string.h 2006-05-30 18:15:44.000000000 -0700
@@ -202,20 +202,20 @@ return __res;
static __always_inline void * __memcpy(void * to, const void * from, size_t n)
{
-int d0, d1, d2;
+int d0, d1, d2, d3;
__asm__ __volatile__(
"rep ; movsl\n\t"
- "movl %4,%%ecx\n\t"
- "andl $3,%%ecx\n\t"
-#if 1 /* want to pay 2 byte penalty for a chance to skip microcoded rep? */
+ "andl $3,%3\n\t"
+#if 1 /* want to pay 2 byte penalty for a chance to skip a mov and a microcoded rep? */
"jz 1f\n\t"
#endif
+ "movl %3,%%ecx\n\t"
"rep ; movsb\n\t"
"1:"
- : "=&c" (d0), "=&D" (d1), "=&S" (d2)
- : "0" (n/4), "g" (n), "1" ((long) to), "2" ((long) from)
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2), "=&g" (d3)
+ : "0" (n/4), "1" ((long) to), "2" ((long) from), "3" (n)
: "memory");
-return (to);
+return to;
}
/*
_
Patches currently in -mm which might be from 76306.1226@xxxxxxxxxxxxxx are
i386-let-usermode-execute-the-enter.patch
i386-fix-get_segment_eip-with-vm86.patch
i386-memcpy-use-as-few-moves-as.patch
i386-memcpy-minor-optimization.patch
-
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