kernel_optimize_test/arch/x86_64/lib/memcpy.S
Andi Kleen 7bcd3f34e2 [PATCH] x86_64: Undo the earlier changes to remove unrolled copy/memset functions
They cause quite bad performance regressions on Netburst
This is temporary until we can get new optimized functions
for these CPUs.

This undoes changes that were done in 2.6.15 and in 2.6.16-rc1,
essentially bringing the code back to 2.6.14 level. Only change
is I renamed the X86_FEATURE_K8_C flag to X86_FEATURE_REP_GOOD
and fixed the check for the flag and also fixed some comments.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-04 16:43:13 -08:00

122 lines
1.6 KiB
ArmAsm

/* Copyright 2002 Andi Kleen */
#include <asm/cpufeature.h>
/*
* memcpy - Copy a memory block.
*
* Input:
* rdi destination
* rsi source
* rdx count
*
* Output:
* rax original destination
*/
.globl __memcpy
.globl memcpy
.p2align 4
__memcpy:
memcpy:
pushq %rbx
movq %rdi,%rax
movl %edx,%ecx
shrl $6,%ecx
jz .Lhandle_tail
.p2align 4
.Lloop_64:
decl %ecx
movq (%rsi),%r11
movq 8(%rsi),%r8
movq %r11,(%rdi)
movq %r8,1*8(%rdi)
movq 2*8(%rsi),%r9
movq 3*8(%rsi),%r10
movq %r9,2*8(%rdi)
movq %r10,3*8(%rdi)
movq 4*8(%rsi),%r11
movq 5*8(%rsi),%r8
movq %r11,4*8(%rdi)
movq %r8,5*8(%rdi)
movq 6*8(%rsi),%r9
movq 7*8(%rsi),%r10
movq %r9,6*8(%rdi)
movq %r10,7*8(%rdi)
leaq 64(%rsi),%rsi
leaq 64(%rdi),%rdi
jnz .Lloop_64
.Lhandle_tail:
movl %edx,%ecx
andl $63,%ecx
shrl $3,%ecx
jz .Lhandle_7
.p2align 4
.Lloop_8:
decl %ecx
movq (%rsi),%r8
movq %r8,(%rdi)
leaq 8(%rdi),%rdi
leaq 8(%rsi),%rsi
jnz .Lloop_8
.Lhandle_7:
movl %edx,%ecx
andl $7,%ecx
jz .Lende
.p2align 4
.Lloop_1:
movb (%rsi),%r8b
movb %r8b,(%rdi)
incq %rdi
incq %rsi
decl %ecx
jnz .Lloop_1
.Lende:
popq %rbx
ret
.Lfinal:
/* Some CPUs run faster using the string copy instructions.
It is also a lot simpler. Use this when possible */
.section .altinstructions,"a"
.align 8
.quad memcpy
.quad memcpy_c
.byte X86_FEATURE_REP_GOOD
.byte .Lfinal-memcpy
.byte memcpy_c_end-memcpy_c
.previous
.section .altinstr_replacement,"ax"
/* rdi destination
* rsi source
* rdx count
*/
memcpy_c:
movq %rdi,%rax
movl %edx,%ecx
shrl $3,%ecx
andl $7,%edx
rep
movsq
movl %edx,%ecx
rep
movsb
ret
memcpy_c_end:
.previous