diff options
Diffstat (limited to 'sysdeps/x86_64/multiarch/strlen.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/strlen.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/strlen.S b/sysdeps/x86_64/multiarch/strlen.S new file mode 100644 index 0000000000..ab29ceff21 --- /dev/null +++ b/sysdeps/x86_64/multiarch/strlen.S @@ -0,0 +1,68 @@ +/* Multiple versions of strlen(str) -- determine the length of the string STR. + All versions must be listed in ifunc-impl-list.c. + Copyright (C) 2009-2013 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, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> +#include <init-arch.h> + + +/* Define multiple versions only for the definition in libc and for + the DSO. In static binaries we need strlen before the initialization + happened. */ +#if defined SHARED && !defined NOT_IN_libc + .text +ENTRY(strlen) + .type strlen, @gnu_indirect_function + cmpl $0, __cpu_features+KIND_OFFSET(%rip) + jne 1f + call __init_cpu_features +1: leaq __strlen_sse2_pminub(%rip), %rax + testl $bit_Prefer_PMINUB_for_stringop, __cpu_features+FEATURE_OFFSET+index_Prefer_PMINUB_for_stringop(%rip) + jnz 2f + leaq __strlen_sse2(%rip), %rax + testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip) + jz 2f + leaq __strlen_sse42(%rip), %rax + ret +2: testl $bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip) + jz 3f + leaq __strlen_sse2_no_bsf(%rip), %rax +3: ret +END(strlen) + +# undef ENTRY +# define ENTRY(name) \ + .type __strlen_sse2, @function; \ + .align 16; \ + .globl __strlen_sse2; \ + .hidden __strlen_sse2; \ + __strlen_sse2: cfi_startproc; \ + CALL_MCOUNT +# undef END +# define END(name) \ + cfi_endproc; .size __strlen_sse2, .-__strlen_sse2 +# undef libc_hidden_builtin_def +/* It doesn't make sense to send libc-internal strlen calls through a PLT. + The speedup we get from using SSE4.2 instruction is likely eaten away + by the indirect call in the PLT. */ +# define libc_hidden_builtin_def(name) \ + .globl __GI_strlen; __GI_strlen = __strlen_sse2 +#endif + +#include "../strlen.S" |