1 /* strlen(str) -- determine the length of the string STR.
2 Copyright (C) 2009, 2010 Free Software Foundation, Inc.
3 Contributed by Ulrich Drepper <drepper@redhat.com>.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
22 #include <init-arch.h>
25 /* Define multiple versions only for the definition in libc and for
26 the DSO. In static binaries we need strlen before the initialization
28 #if defined SHARED && !defined NOT_IN_libc
31 .type strlen, @gnu_indirect_function
32 cmpl $0, __cpu_features+KIND_OFFSET(%rip)
34 call __init_cpu_features
35 1: leaq __strlen_sse2_pminub(%rip), %rax
36 testl $bit_Prefer_PMINUB_for_stringop, __cpu_features+FEATURE_OFFSET+index_Prefer_PMINUB_for_stringop(%rip)
38 leaq __strlen_sse2(%rip), %rax
39 testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
41 leaq __strlen_sse42(%rip), %rax
43 2: testl $bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip)
45 leaq __strlen_no_bsf(%rip), %rax
50 # define ENTRY(name) \
51 .type __strlen_sse2, @function; \
53 __strlen_sse2: cfi_startproc; \
57 cfi_endproc; .size __strlen_sse2, .-__strlen_sse2
58 # undef libc_hidden_builtin_def
59 /* It doesn't make sense to send libc-internal strlen calls through a PLT.
60 The speedup we get from using SSE4.2 instruction is likely eaten away
61 by the indirect call in the PLT. */
62 # define libc_hidden_builtin_def(name) \
63 .globl __GI_strlen; __GI_strlen = __strlen_sse2
66 #include "../strlen.S"