linux/arch/x86_64/lib/copy_page.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

102 lines
1.9 KiB
ArmAsm

/* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */
/* Don't use streaming store because it's better when the target
ends up in cache. */
/* Could vary the prefetch distance based on SMP/UP */
.globl copy_page
.p2align 4
copy_page:
subq $3*8,%rsp
movq %rbx,(%rsp)
movq %r12,1*8(%rsp)
movq %r13,2*8(%rsp)
movl $(4096/64)-5,%ecx
.p2align 4
.Loop64:
dec %rcx
movq (%rsi), %rax
movq 8 (%rsi), %rbx
movq 16 (%rsi), %rdx
movq 24 (%rsi), %r8
movq 32 (%rsi), %r9
movq 40 (%rsi), %r10
movq 48 (%rsi), %r11
movq 56 (%rsi), %r12
prefetcht0 5*64(%rsi)
movq %rax, (%rdi)
movq %rbx, 8 (%rdi)
movq %rdx, 16 (%rdi)
movq %r8, 24 (%rdi)
movq %r9, 32 (%rdi)
movq %r10, 40 (%rdi)
movq %r11, 48 (%rdi)
movq %r12, 56 (%rdi)
leaq 64 (%rsi), %rsi
leaq 64 (%rdi), %rdi
jnz .Loop64
movl $5,%ecx
.p2align 4
.Loop2:
decl %ecx
movq (%rsi), %rax
movq 8 (%rsi), %rbx
movq 16 (%rsi), %rdx
movq 24 (%rsi), %r8
movq 32 (%rsi), %r9
movq 40 (%rsi), %r10
movq 48 (%rsi), %r11
movq 56 (%rsi), %r12
movq %rax, (%rdi)
movq %rbx, 8 (%rdi)
movq %rdx, 16 (%rdi)
movq %r8, 24 (%rdi)
movq %r9, 32 (%rdi)
movq %r10, 40 (%rdi)
movq %r11, 48 (%rdi)
movq %r12, 56 (%rdi)
leaq 64(%rdi),%rdi
leaq 64(%rsi),%rsi
jnz .Loop2
movq (%rsp),%rbx
movq 1*8(%rsp),%r12
movq 2*8(%rsp),%r13
addq $3*8,%rsp
ret
/* Some CPUs run faster using the string copy instructions.
It is also a lot simpler. Use this when possible */
#include <asm/cpufeature.h>
.section .altinstructions,"a"
.align 8
.quad copy_page
.quad copy_page_c
.byte X86_FEATURE_REP_GOOD
.byte copy_page_c_end-copy_page_c
.byte copy_page_c_end-copy_page_c
.previous
.section .altinstr_replacement,"ax"
copy_page_c:
movl $4096/8,%ecx
rep
movsq
ret
copy_page_c_end:
.previous