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102 lines
2.2 KiB
ArmAsm
102 lines
2.2 KiB
ArmAsm
/* strlen(str) -- determine the length of the string STR.
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Copyright (C) 2009-2013 Free Software Foundation, Inc.
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Contributed by Ulrich Drepper <drepper@redhat.com>.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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.text
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ENTRY(strlen)
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xor %rax, %rax
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mov %edi, %ecx
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and $0x3f, %ecx
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pxor %xmm0, %xmm0
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cmp $0x30, %ecx
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ja L(next)
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movdqu (%rdi), %xmm1
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pcmpeqb %xmm1, %xmm0
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pmovmskb %xmm0, %edx
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test %edx, %edx
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jnz L(exit_less16)
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mov %rdi, %rax
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and $-16, %rax
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jmp L(align16_start)
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L(next):
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mov %rdi, %rax
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and $-16, %rax
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pcmpeqb (%rax), %xmm0
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mov $-1, %esi
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sub %rax, %rcx
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shl %cl, %esi
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pmovmskb %xmm0, %edx
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and %esi, %edx
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jnz L(exit)
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L(align16_start):
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pxor %xmm0, %xmm0
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pxor %xmm1, %xmm1
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pxor %xmm2, %xmm2
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pxor %xmm3, %xmm3
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.p2align 4
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L(align16_loop):
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pcmpeqb 16(%rax), %xmm0
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pmovmskb %xmm0, %edx
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test %edx, %edx
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jnz L(exit16)
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pcmpeqb 32(%rax), %xmm1
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pmovmskb %xmm1, %edx
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test %edx, %edx
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jnz L(exit32)
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pcmpeqb 48(%rax), %xmm2
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pmovmskb %xmm2, %edx
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test %edx, %edx
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jnz L(exit48)
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pcmpeqb 64(%rax), %xmm3
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pmovmskb %xmm3, %edx
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lea 64(%rax), %rax
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test %edx, %edx
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jz L(align16_loop)
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L(exit):
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sub %rdi, %rax
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L(exit_less16):
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bsf %rdx, %rdx
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add %rdx, %rax
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ret
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.p2align 4
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L(exit16):
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sub %rdi, %rax
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bsf %rdx, %rdx
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lea 16(%rdx,%rax), %rax
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ret
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.p2align 4
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L(exit32):
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sub %rdi, %rax
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bsf %rdx, %rdx
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lea 32(%rdx,%rax), %rax
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ret
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.p2align 4
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L(exit48):
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sub %rdi, %rax
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bsf %rdx, %rdx
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lea 48(%rdx,%rax), %rax
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ret
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END(strlen)
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libc_hidden_builtin_def (strlen)
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