/* Copyright 2002 Andi Kleen */
#include <linux/linkage.h>
#include <asm/dwarf2.h>
#include <asm/cpufeature.h>
/*
* memcpy - Copy a memory block.
*
* Input:
* rdi destination
* rsi source
* rdx count
*
* Output:
* rax original destination
*/
ALIGN
memcpy_c:
CFI_STARTPROC
movq %rdi,%rax
movl %edx,%ecx
shrl $3,%ecx
andl $7,%edx
rep movsq
movl %edx,%ecx
rep movsb
ret
CFI_ENDPROC
ENDPROC(memcpy_c)
ENTRY(__memcpy)
ENTRY(memcpy)
CFI_STARTPROC
pushq %rbx
CFI_ADJUST_CFA_OFFSET 8
CFI_REL_OFFSET rbx, 0
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
CFI_ADJUST_CFA_OFFSET -8
CFI_RESTORE rbx
ret
.Lfinal:
CFI_ENDPROC
ENDPROC(memcpy)
ENDPROC(__memcpy)
/* Some CPUs run faster using the string copy instructions.
It is also a lot simpler. Use this when possible */
.section .altinstr_replacement,"ax"
1: .byte 0xeb /* jmp <disp8> */
.byte (memcpy_c - memcpy) - (2f - 1b) /* offset */
2:
.previous
.section .altinstructions,"a"
.align 8
.quad memcpy
.quad 1b
.byte X86_FEATURE_REP_GOOD
/* Replace only beginning, memcpy is used to apply alternatives, so it
* is silly to overwrite itself with nops - reboot is only outcome... */
.byte 2b - 1b
.byte 2b - 1b
.previous
