/* Copyright 2002 Andi Kleen, SuSE Labs */ /* * ISO C memset - set a memory block to a byte value. * * rdi destination * rsi value (char) * rdx count (bytes) * * rax original destination */ .globl __memset .globl memset .p2align 4 memset: __memset: movq %rdi,%r10 movq %rdx,%r11 /* expand byte value */ movzbl %sil,%ecx movabs $0x0101010101010101,%rax mul %rcx /* with rax, clobbers rdx */ /* align dst */ movl %edi,%r9d andl $7,%r9d jnz .Lbad_alignment .Lafter_bad_alignment: movl %r11d,%ecx shrl $6,%ecx jz .Lhandle_tail .p2align 4 .Lloop_64: decl %ecx movq %rax,(%rdi) movq %rax,8(%rdi) movq %rax,16(%rdi) movq %rax,24(%rdi) movq %rax,32(%rdi) movq %rax,40(%rdi) movq %rax,48(%rdi) movq %rax,56(%rdi) leaq 64(%rdi),%rdi jnz .Lloop_64 /* Handle tail in loops. The loops should be faster than hard to predict jump tables. */ .p2align 4 .Lhandle_tail: movl %r11d,%ecx andl $63&(~7),%ecx jz .Lhandle_7 shrl $3,%ecx .p2align 4 .Lloop_8: decl %ecx movq %rax,(%rdi) leaq 8(%rdi),%rdi jnz .Lloop_8 .Lhandle_7: movl %r11d,%ecx andl $7,%ecx jz .Lende .p2align 4 .Lloop_1: decl %ecx movb %al,(%rdi) leaq 1(%rdi),%rdi jnz .Lloop_1 .Lende: movq %r10,%rax ret .Lbad_alignment: cmpq $7,%r11 jbe .Lhandle_7 movq %rax,(%rdi) /* unaligned store */ movq $8,%r8 subq %r9,%r8 addq %r8,%rdi subq %r8,%r11 jmp .Lafter_bad_alignment