057e05c1d6
Support memmove() by enhanced rep movsb. On processors supporting enhanced REP MOVSB/STOSB, the alternative memmove() function using enhanced rep movsb overrides the original function. The patch doesn't change the backward memmove case to use enhanced rep movsb. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1305671358-14478-9-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
225 lines
3.7 KiB
ArmAsm
225 lines
3.7 KiB
ArmAsm
/*
|
|
* Normally compiler builtins are used, but sometimes the compiler calls out
|
|
* of line code. Based on asm-i386/string.h.
|
|
*
|
|
* This assembly file is re-written from memmove_64.c file.
|
|
* - Copyright 2011 Fenghua Yu <fenghua.yu@intel.com>
|
|
*/
|
|
#define _STRING_C
|
|
#include <linux/linkage.h>
|
|
#include <asm/dwarf2.h>
|
|
#include <asm/cpufeature.h>
|
|
|
|
#undef memmove
|
|
|
|
/*
|
|
* Implement memmove(). This can handle overlap between src and dst.
|
|
*
|
|
* Input:
|
|
* rdi: dest
|
|
* rsi: src
|
|
* rdx: count
|
|
*
|
|
* Output:
|
|
* rax: dest
|
|
*/
|
|
ENTRY(memmove)
|
|
CFI_STARTPROC
|
|
|
|
/* Handle more 32bytes in loop */
|
|
mov %rdi, %rax
|
|
cmp $0x20, %rdx
|
|
jb 1f
|
|
|
|
/* Decide forward/backward copy mode */
|
|
cmp %rdi, %rsi
|
|
jge .Lmemmove_begin_forward
|
|
mov %rsi, %r8
|
|
add %rdx, %r8
|
|
cmp %rdi, %r8
|
|
jg 2f
|
|
|
|
.Lmemmove_begin_forward:
|
|
/*
|
|
* movsq instruction have many startup latency
|
|
* so we handle small size by general register.
|
|
*/
|
|
cmp $680, %rdx
|
|
jb 3f
|
|
/*
|
|
* movsq instruction is only good for aligned case.
|
|
*/
|
|
|
|
cmpb %dil, %sil
|
|
je 4f
|
|
3:
|
|
sub $0x20, %rdx
|
|
/*
|
|
* We gobble 32byts forward in each loop.
|
|
*/
|
|
5:
|
|
sub $0x20, %rdx
|
|
movq 0*8(%rsi), %r11
|
|
movq 1*8(%rsi), %r10
|
|
movq 2*8(%rsi), %r9
|
|
movq 3*8(%rsi), %r8
|
|
leaq 4*8(%rsi), %rsi
|
|
|
|
movq %r11, 0*8(%rdi)
|
|
movq %r10, 1*8(%rdi)
|
|
movq %r9, 2*8(%rdi)
|
|
movq %r8, 3*8(%rdi)
|
|
leaq 4*8(%rdi), %rdi
|
|
jae 5b
|
|
addq $0x20, %rdx
|
|
jmp 1f
|
|
/*
|
|
* Handle data forward by movsq.
|
|
*/
|
|
.p2align 4
|
|
4:
|
|
movq %rdx, %rcx
|
|
movq -8(%rsi, %rdx), %r11
|
|
lea -8(%rdi, %rdx), %r10
|
|
shrq $3, %rcx
|
|
rep movsq
|
|
movq %r11, (%r10)
|
|
jmp 13f
|
|
.Lmemmove_end_forward:
|
|
|
|
/*
|
|
* Handle data backward by movsq.
|
|
*/
|
|
.p2align 4
|
|
7:
|
|
movq %rdx, %rcx
|
|
movq (%rsi), %r11
|
|
movq %rdi, %r10
|
|
leaq -8(%rsi, %rdx), %rsi
|
|
leaq -8(%rdi, %rdx), %rdi
|
|
shrq $3, %rcx
|
|
std
|
|
rep movsq
|
|
cld
|
|
movq %r11, (%r10)
|
|
jmp 13f
|
|
|
|
/*
|
|
* Start to prepare for backward copy.
|
|
*/
|
|
.p2align 4
|
|
2:
|
|
cmp $680, %rdx
|
|
jb 6f
|
|
cmp %dil, %sil
|
|
je 7b
|
|
6:
|
|
/*
|
|
* Calculate copy position to tail.
|
|
*/
|
|
addq %rdx, %rsi
|
|
addq %rdx, %rdi
|
|
subq $0x20, %rdx
|
|
/*
|
|
* We gobble 32byts backward in each loop.
|
|
*/
|
|
8:
|
|
subq $0x20, %rdx
|
|
movq -1*8(%rsi), %r11
|
|
movq -2*8(%rsi), %r10
|
|
movq -3*8(%rsi), %r9
|
|
movq -4*8(%rsi), %r8
|
|
leaq -4*8(%rsi), %rsi
|
|
|
|
movq %r11, -1*8(%rdi)
|
|
movq %r10, -2*8(%rdi)
|
|
movq %r9, -3*8(%rdi)
|
|
movq %r8, -4*8(%rdi)
|
|
leaq -4*8(%rdi), %rdi
|
|
jae 8b
|
|
/*
|
|
* Calculate copy position to head.
|
|
*/
|
|
addq $0x20, %rdx
|
|
subq %rdx, %rsi
|
|
subq %rdx, %rdi
|
|
1:
|
|
cmpq $16, %rdx
|
|
jb 9f
|
|
/*
|
|
* Move data from 16 bytes to 31 bytes.
|
|
*/
|
|
movq 0*8(%rsi), %r11
|
|
movq 1*8(%rsi), %r10
|
|
movq -2*8(%rsi, %rdx), %r9
|
|
movq -1*8(%rsi, %rdx), %r8
|
|
movq %r11, 0*8(%rdi)
|
|
movq %r10, 1*8(%rdi)
|
|
movq %r9, -2*8(%rdi, %rdx)
|
|
movq %r8, -1*8(%rdi, %rdx)
|
|
jmp 13f
|
|
.p2align 4
|
|
9:
|
|
cmpq $8, %rdx
|
|
jb 10f
|
|
/*
|
|
* Move data from 8 bytes to 15 bytes.
|
|
*/
|
|
movq 0*8(%rsi), %r11
|
|
movq -1*8(%rsi, %rdx), %r10
|
|
movq %r11, 0*8(%rdi)
|
|
movq %r10, -1*8(%rdi, %rdx)
|
|
jmp 13f
|
|
10:
|
|
cmpq $4, %rdx
|
|
jb 11f
|
|
/*
|
|
* Move data from 4 bytes to 7 bytes.
|
|
*/
|
|
movl (%rsi), %r11d
|
|
movl -4(%rsi, %rdx), %r10d
|
|
movl %r11d, (%rdi)
|
|
movl %r10d, -4(%rdi, %rdx)
|
|
jmp 13f
|
|
11:
|
|
cmp $2, %rdx
|
|
jb 12f
|
|
/*
|
|
* Move data from 2 bytes to 3 bytes.
|
|
*/
|
|
movw (%rsi), %r11w
|
|
movw -2(%rsi, %rdx), %r10w
|
|
movw %r11w, (%rdi)
|
|
movw %r10w, -2(%rdi, %rdx)
|
|
jmp 13f
|
|
12:
|
|
cmp $1, %rdx
|
|
jb 13f
|
|
/*
|
|
* Move data for 1 byte.
|
|
*/
|
|
movb (%rsi), %r11b
|
|
movb %r11b, (%rdi)
|
|
13:
|
|
retq
|
|
CFI_ENDPROC
|
|
|
|
.section .altinstr_replacement,"ax"
|
|
.Lmemmove_begin_forward_efs:
|
|
/* Forward moving data. */
|
|
movq %rdx, %rcx
|
|
rep movsb
|
|
retq
|
|
.Lmemmove_end_forward_efs:
|
|
.previous
|
|
|
|
.section .altinstructions,"a"
|
|
.align 8
|
|
.quad .Lmemmove_begin_forward
|
|
.quad .Lmemmove_begin_forward_efs
|
|
.word X86_FEATURE_ERMS
|
|
.byte .Lmemmove_end_forward-.Lmemmove_begin_forward
|
|
.byte .Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs
|
|
.previous
|
|
ENDPROC(memmove)
|