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arch/x86/memcpy.c: Optimize code for 64bit 

In 64bit movsq is available which moves memory in chunks of 8 bytes
rather than 4 bytes.

Linux uses the same code.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: I65f178d2ed3aae54b0c1ce739c2b4af8738b9fcc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78646
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Eric Lai <ericllai@google.com>
This commit is contained in:
Arthur Heymans 2023-10-25 08:22:49 +02:00 committed by Martin L Roth
parent 8bd7d6c806
commit fdf85614dc
1 changed files with 10 additions and 3 deletions
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13
src/arch/x86/memcpy.c
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@ -14,19 +14,26 @@ void *memcpy(void *dest, const void *src, size_t n)
check_memory_region((unsigned long)dest, n, true, _RET_IP_);
#endif
asm volatile(
#if ENV_X86_64
"rep ; movsd\n\t"
asm volatile(
"rep ; movsq\n\t"
"mov %4,%%rcx\n\t"
"rep ; movsb\n\t"
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
: "memory"
);
#else
asm volatile(
"rep ; movsl\n\t"
"movl %4,%%ecx\n\t"
#endif
"rep ; movsb\n\t"
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
: "memory"
);
#endif
return dest;
}