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126 lines
3.0 KiB
ArmAsm
126 lines
3.0 KiB
ArmAsm
/* strlen(str) -- determine the length of the string STR.
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Copyright (C) 2009 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sysdep.h>
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#include <init-arch.h>
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/* Define multiple versions only for the definition in libc and for
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the DSO. In static binaries we need strlen before the initialization
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happened. */
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#if defined SHARED && !defined NOT_IN_libc
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.text
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ENTRY(strlen)
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.type strlen, @gnu_indirect_function
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cmpl $0, __cpu_features+KIND_OFFSET(%rip)
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jne 1f
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call __init_cpu_features
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1: leaq __strlen_sse2(%rip), %rax
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testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
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jz 2f
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leaq __strlen_sse42(%rip), %rax
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2: ret
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END(strlen)
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.section .text.sse4.2,"ax",@progbits
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.align 16
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.type __strlen_sse42, @function
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__strlen_sse42:
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cfi_startproc
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CALL_MCOUNT
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pxor %xmm1, %xmm1
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movl %edi, %ecx
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movq %rdi, %r8
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andq $~15, %rdi
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xor %edi, %ecx
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pcmpeqb (%rdi), %xmm1
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pmovmskb %xmm1, %edx
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shrl %cl, %edx
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shll %cl, %edx
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andl %edx, %edx
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jnz L(less16bytes)
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pxor %xmm1, %xmm1
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.p2align 4
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L(more64bytes_loop):
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pcmpistri $0x08, 16(%rdi), %xmm1
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jz L(more32bytes)
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pcmpistri $0x08, 32(%rdi), %xmm1
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jz L(more48bytes)
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pcmpistri $0x08, 48(%rdi), %xmm1
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jz L(more64bytes)
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add $64, %rdi
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pcmpistri $0x08, (%rdi), %xmm1
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jnz L(more64bytes_loop)
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leaq (%rdi,%rcx), %rax
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subq %r8, %rax
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ret
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.p2align 4
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L(more32bytes):
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leaq 16(%rdi,%rcx, 1), %rax
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subq %r8, %rax
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ret
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.p2align 4
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L(more48bytes):
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leaq 32(%rdi,%rcx, 1), %rax
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subq %r8, %rax
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ret
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.p2align 4
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L(more64bytes):
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leaq 48(%rdi,%rcx, 1), %rax
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subq %r8, %rax
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ret
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.p2align 4
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L(less16bytes):
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subq %r8, %rdi
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bsfl %edx, %eax
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addq %rdi, %rax
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ret
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cfi_endproc
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.size __strlen_sse42, .-__strlen_sse42
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# undef ENTRY
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# define ENTRY(name) \
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.type __strlen_sse2, @function; \
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.align 16; \
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__strlen_sse2: cfi_startproc; \
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CALL_MCOUNT
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# undef END
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# define END(name) \
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cfi_endproc; .size __strlen_sse2, .-__strlen_sse2
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# undef libc_hidden_builtin_def
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/* It doesn't make sense to send libc-internal strlen calls through a PLT.
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The speedup we get from using SSE4.2 instruction is likely eaten away
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by the indirect call in the PLT. */
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# define libc_hidden_builtin_def(name) \
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.globl __GI_strlen; __GI_strlen = __strlen_sse2
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#endif
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#include "../strlen.S"
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