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authorStefan Reinauer <reinauer@google.com>2012-08-22 17:01:08 -0700
committerStefan Reinauer <stefan.reinauer@coreboot.org>2012-11-08 19:40:26 +0100
commit31409617a46c5ac6ef1a893d3c478f76ce4d7d3d (patch)
tree28ab73ff80d809a7f4de38788cd07eecc2d55345 /src/arch
parent4b1610d766aa1ea0c825b39600fe8a3eb6d2a6be (diff)
x86 memcpy: Copy 4 bytes at once
This is a slight improvement over the rep movsb loop Change-Id: Id71d9bfe5330b154a5c62fac85ce3955ae89b057 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-on: http://review.coreboot.org/1742 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Diffstat (limited to 'src/arch')
-rw-r--r--src/arch/x86/lib/memcpy.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/src/arch/x86/lib/memcpy.c b/src/arch/x86/lib/memcpy.c
index f8607cfc50..7f079ce9d6 100644
--- a/src/arch/x86/lib/memcpy.c
+++ b/src/arch/x86/lib/memcpy.c
@@ -5,11 +5,13 @@ void *memcpy(void *dest, const void *src, size_t n)
unsigned long d0, d1, d2;
asm volatile(
- "rep movsb"
- : "=S"(d0), "=D"(d1), "=c"(d2)
- : "0"(src), "1"(dest), "2"(n)
+ "rep ; movsl\n\t"
+ "movl %4,%%ecx\n\t"
+ "rep ; movsb\n\t"
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+ : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
: "memory"
- );
+ );
return dest;
}