/* memcmp with SSE2 Copyright (C) 2009 Free Software Foundation, Inc. Contributed by Intel Corporation. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include .text ENTRY (memcmp) test %rdx, %rdx jz L(finz) cmpq $1, %rdx jle L(finr1b) subq %rdi, %rsi movq %rdx, %r10 cmpq $32, %r10 jge L(gt32) /* Handle small chunks and last block of less than 32 bytes. */ L(small): testq $1, %r10 jz L(s2b) movzbl (%rdi), %eax movzbl (%rdi, %rsi), %edx subq $1, %r10 je L(finz1) addq $1, %rdi subl %edx, %eax jnz L(exit) L(s2b): testq $2, %r10 jz L(s4b) movzwl (%rdi), %eax movzwl (%rdi, %rsi), %edx subq $2, %r10 je L(fin2_7) addq $2, %rdi cmpl %edx, %eax jnz L(fin2_7) L(s4b): testq $4, %r10 jz L(s8b) movl (%rdi), %eax movl (%rdi, %rsi), %edx subq $4, %r10 je L(fin2_7) addq $4, %rdi cmpl %edx, %eax jnz L(fin2_7) L(s8b): testq $8, %r10 jz L(s16b) movq (%rdi), %rax movq (%rdi, %rsi), %rdx subq $8, %r10 je L(fin2_7) addq $8, %rdi cmpq %rdx, %rax jnz L(fin2_7) L(s16b): movdqu (%rdi), %xmm1 movdqu (%rdi, %rsi), %xmm0 pcmpeqb %xmm0, %xmm1 pmovmskb %xmm1, %edx xorl %eax, %eax subl $0xffff, %edx jz L(finz) bsfl %edx, %ecx leaq (%rdi, %rcx), %rcx movzbl (%rcx), %eax movzbl (%rsi, %rcx), %edx jmp L(finz1) .p2align 4,, 4 L(finr1b): movzbl (%rdi), %eax movzbl (%rsi), %edx L(finz1): subl %edx, %eax L(exit): ret .p2align 4,, 4 L(fin2_7): cmpq %rdx, %rax jz L(finz) movq %rax, %r11 subq %rdx, %r11 bsfq %r11, %rcx sarq $3, %rcx salq $3, %rcx sarq %cl, %rax movzbl %al, %eax sarq %cl, %rdx movzbl %dl, %edx subl %edx, %eax ret .p2align 4,, 4 L(finz): xorl %eax, %eax ret /* For blocks bigger than 32 bytes 1. Advance one of the addr pointer to be 16B aligned. 2. Treat the case of both addr pointers aligned to 16B separately to avoid movdqu. 3. Handle any blocks of greater than 64 consecutive bytes with unrolling to reduce branches. 4. At least one addr pointer is 16B aligned, use memory version of pcmbeqb. */ .p2align 4,, 4 L(gt32): movq %rdx, %r11 addq %rdi, %r11 movq %rdi, %r8 andq $15, %r8 jz L(16am) /* Both pointers may be misaligned. */ movdqu (%rdi), %xmm1 movdqu (%rdi, %rsi), %xmm0 pcmpeqb %xmm0, %xmm1 pmovmskb %xmm1, %edx subl $0xffff, %edx jnz L(neq) neg %r8 leaq 16(%rdi, %r8), %rdi L(16am): /* Handle two 16B aligned pointers separately. */ testq $15, %rsi jz L(ATR) testq $16, %rdi jz L(A32) movdqu (%rdi, %rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi L(A32): movq %r11, %r10 andq $-32, %r10 cmpq %r10, %rdi jge L(mt16) /* Pre-unroll to be ready for unrolled 64B loop. */ testq $32, %rdi jz L(A64) movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi L(A64): movq %r11, %r10 andq $-64, %r10 cmpq %r10, %rdi jge L(mt32) L(A64main): movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi cmpq %rdi, %r10 jne L(A64main) L(mt32): movq %r11, %r10 andq $-32, %r10 cmpq %r10, %rdi jge L(mt16) L(A32main): movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqu (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi cmpq %rdi, %r10 jne L(A32main) L(mt16): subq %rdi, %r11 je L(finz) movq %r11, %r10 jmp L(small) .p2align 4,, 4 L(neq): bsfl %edx, %ecx movzbl (%rdi, %rcx), %eax addq %rdi, %rsi movzbl (%rsi,%rcx), %edx jmp L(finz1) .p2align 4,, 4 L(ATR): movq %r11, %r10 andq $-32, %r10 cmpq %r10, %rdi jge L(mt16) testq $16, %rdi jz L(ATR32) movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi cmpq %rdi, %r10 je L(mt16) L(ATR32): movq %r11, %r10 andq $-64, %r10 testq $32, %rdi jz L(ATR64) movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi L(ATR64): cmpq %rdi, %r10 je L(mt32) L(ATR64main): movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi cmpq %rdi, %r10 jne L(ATR64main) movq %r11, %r10 andq $-32, %r10 cmpq %r10, %rdi jge L(mt16) L(ATR32res): movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi movdqa (%rdi,%rsi), %xmm0 pcmpeqb (%rdi), %xmm0 pmovmskb %xmm0, %edx subl $0xffff, %edx jnz L(neq) addq $16, %rdi cmpq %r10, %rdi jne L(ATR32res) subq %rdi, %r11 je L(finz) movq %r11, %r10 jmp L(small) /* Align to 16byte to improve instruction fetch. */ .p2align 4,, 4 END(memcmp) #undef bcmp weak_alias (memcmp, bcmp) libc_hidden_builtin_def (memcmp)