/* 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 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 bad_alignment after_bad_alignment: movq %r11,%rcx movl $64,%r8d shrq $6,%rcx jz handle_tail loop_64: 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) addq %r8,%rdi decl %ecx jnz loop_64 /* Handle tail in loops. The loops should be faster than hard to predict jump tables. */ handle_tail: movl %r11d,%ecx andl $63&(~7),%ecx jz handle_7 shrl $3,%ecx loop_8: movq %rax,(%rdi) addq $8,%rdi decl %ecx jnz loop_8 handle_7: movl %r11d,%ecx andl $7,%ecx jz ende loop_1: movb %al,(%rdi) addq $1,%rdi decl %ecx jnz loop_1 ende: movq %r10,%rax ret bad_alignment: cmpq $7,%r11 jbe handle_7 movq %rax,(%rdi) /* unaligned store */ movq $8,%r8 subq %r9,%r8 addq %r8,%rdi subq %r8,%r11 jmp after_bad_alignment