2010-07-26 15:37:08 +00:00
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/* strnlen(str,maxlen) -- determine the length of the string STR up to MAXLEN.
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Copyright (C) 2010 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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2012-02-09 23:18:22 +00:00
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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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2010-07-26 15:37:08 +00:00
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#include <sysdep.h>
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.text
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ENTRY(__strnlen)
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movq %rsi, %rax
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testq %rsi, %rsi
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jz 3f
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pxor %xmm2, %xmm2
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movq %rdi, %rcx
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movq %rdi, %r8
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movq $16, %r9
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andq $~15, %rdi
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movdqa %xmm2, %xmm1
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pcmpeqb (%rdi), %xmm2
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orl $0xffffffff, %r10d
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subq %rdi, %rcx
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shll %cl, %r10d
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subq %rcx, %r9
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pmovmskb %xmm2, %edx
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andl %r10d, %edx
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jnz 1f
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subq %r9, %rsi
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jbe 3f
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2: movdqa 16(%rdi), %xmm0
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leaq 16(%rdi), %rdi
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pcmpeqb %xmm1, %xmm0
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pmovmskb %xmm0, %edx
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testl %edx, %edx
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jnz 1f
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subq $16, %rsi
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jnbe 2b
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3: ret
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1: subq %r8, %rdi
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bsfl %edx, %edx
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addq %rdi, %rdx
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cmpq %rdx, %rax
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cmovnbq %rdx, %rax
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ret
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END(__strnlen)
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weak_alias (__strnlen, strnlen)
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libc_hidden_def (strnlen)
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