diff options
Diffstat (limited to 'arch/x86_64/lib/memcpy.S')
| -rw-r--r-- | arch/x86_64/lib/memcpy.S | 93 |
1 files changed, 91 insertions, 2 deletions
diff --git a/arch/x86_64/lib/memcpy.S b/arch/x86_64/lib/memcpy.S index 92dd80544602..5554948b5554 100644 --- a/arch/x86_64/lib/memcpy.S +++ b/arch/x86_64/lib/memcpy.S @@ -11,8 +11,6 @@ * * Output: * rax original destination - * - * TODO: check best memcpy for PSC */ .globl __memcpy @@ -20,6 +18,95 @@ .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 @@ -30,3 +117,5 @@ memcpy: rep movsb ret +memcpy_c_end: + .previous |