| /* 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 |
