| /* strlen(str) -- determine the length of the string STR. |
| Copyright (C) 2009, 2010 Free Software Foundation, Inc. |
| Contributed by Ulrich Drepper <drepper@redhat.com>. |
| 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <sysdep.h> |
| |
| |
| .text |
| ENTRY(strlen) |
| xor %rax, %rax |
| mov %edi, %ecx |
| and $0x3f, %ecx |
| pxor %xmm0, %xmm0 |
| cmp $0x30, %ecx |
| ja L(next) |
| movdqu (%rdi), %xmm1 |
| pcmpeqb %xmm1, %xmm0 |
| pmovmskb %xmm0, %edx |
| test %edx, %edx |
| jnz L(exit_less16) |
| mov %rdi, %rax |
| and $-16, %rax |
| jmp L(align16_start) |
| L(next): |
| mov %rdi, %rax |
| and $-16, %rax |
| pcmpeqb (%rax), %xmm0 |
| mov $-1, %esi |
| sub %rax, %rcx |
| shl %cl, %esi |
| pmovmskb %xmm0, %edx |
| and %esi, %edx |
| jnz L(exit) |
| L(align16_start): |
| pxor %xmm0, %xmm0 |
| pxor %xmm1, %xmm1 |
| pxor %xmm2, %xmm2 |
| pxor %xmm3, %xmm3 |
| .p2align 4 |
| L(align16_loop): |
| pcmpeqb 16(%rax), %xmm0 |
| pmovmskb %xmm0, %edx |
| test %edx, %edx |
| jnz L(exit16) |
| |
| pcmpeqb 32(%rax), %xmm1 |
| pmovmskb %xmm1, %edx |
| test %edx, %edx |
| jnz L(exit32) |
| |
| pcmpeqb 48(%rax), %xmm2 |
| pmovmskb %xmm2, %edx |
| test %edx, %edx |
| jnz L(exit48) |
| |
| pcmpeqb 64(%rax), %xmm3 |
| pmovmskb %xmm3, %edx |
| lea 64(%rax), %rax |
| test %edx, %edx |
| jz L(align16_loop) |
| L(exit): |
| sub %rdi, %rax |
| L(exit_less16): |
| bsf %rdx, %rdx |
| add %rdx, %rax |
| ret |
| .p2align 4 |
| L(exit16): |
| sub %rdi, %rax |
| bsf %rdx, %rdx |
| lea 16(%rdx,%rax), %rax |
| ret |
| .p2align 4 |
| L(exit32): |
| sub %rdi, %rax |
| bsf %rdx, %rdx |
| lea 32(%rdx,%rax), %rax |
| ret |
| .p2align 4 |
| L(exit48): |
| sub %rdi, %rax |
| bsf %rdx, %rdx |
| lea 48(%rdx,%rax), %rax |
| ret |
| END(strlen) |
| libc_hidden_builtin_def (strlen) |