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authorUlrich Drepper <drepper@redhat.com>2009-08-04 18:15:02 -0700
committerUlrich Drepper <drepper@redhat.com>2009-08-04 18:15:02 -0700
commit2c709c6f05ed5cbcf30df89d3aa63b78a38bf968 (patch)
tree6b995472f6c187b9bc77b743726918a34e36ef62
parent02cea47161c00969afa985e641f4ac376f84d35f (diff)
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Add x86 SSE strlen.
-rw-r--r--ChangeLog6
-rw-r--r--sysdeps/i386/i686/multiarch/strcspn.S6
-rw-r--r--sysdeps/i386/i686/multiarch/strlen.S154
-rw-r--r--sysdeps/i386/i686/multiarch/strspn.S6
4 files changed, 166 insertions, 6 deletions
diff --git a/ChangeLog b/ChangeLog
index 149f66f..94cfd06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2009-08-03 H.J. Lu <hongjiu.lu@intel.com>
+ * sysdeps/i386/i686/multiarch/strcspn.S: Add comments for no
+ hidden IFUNC functions.
+ * sysdeps/i386/i686/multiarch/strspn.S: Likewise.
+
+ * sysdeps/i386/i686/multiarch/strlen.S: New file.
+
* sysdeps/i386/i686/multiarch/Makefile [subdir=string]
(sysdep_routines): Add strcspn-c, strpbrk-c, strspn-c, strstr-c, and
strcasestr-c.
diff --git a/sysdeps/i386/i686/multiarch/strcspn.S b/sysdeps/i386/i686/multiarch/strcspn.S
index f5ca092..ca9c3f5 100644
--- a/sysdeps/i386/i686/multiarch/strcspn.S
+++ b/sysdeps/i386/i686/multiarch/strcspn.S
@@ -83,9 +83,9 @@ END(STRCSPN)
# define END(name) \
cfi_endproc; .size STRCSPN_IA32, .-STRCSPN_IA32
# undef libc_hidden_builtin_def
-/* It doesn't make sense to send libc-internal strcspn calls through a PLT.
- The speedup we get from using SSE4.2 instruction is likely eaten away
- by the indirect call in the PLT. */
+/* IFUNC doesn't work with the hidden functions in shared library since
+ they will be called without setting up EBX needed for PLT which is
+ used by IFUNC. */
# define libc_hidden_builtin_def(name) \
.globl __GI_STRCSPN; __GI_STRCSPN = STRCSPN_IA32
#endif
diff --git a/sysdeps/i386/i686/multiarch/strlen.S b/sysdeps/i386/i686/multiarch/strlen.S
new file mode 100644
index 0000000..3d4d9f1
--- /dev/null
+++ b/sysdeps/i386/i686/multiarch/strlen.S
@@ -0,0 +1,154 @@
+/* Multiple versions of strlen
+ Copyright (C) 2009 Free Software Foundation, Inc.
+ Contributed by Intel Corporation.
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <sysdep.h>
+#include <ifunc-defines.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
+ .section .gnu.linkonce.t.__i686.get_pc_thunk.bx,"ax",@progbits
+ .globl __i686.get_pc_thunk.bx
+ .hidden __i686.get_pc_thunk.bx
+ .p2align 4
+ .type __i686.get_pc_thunk.bx,@function
+__i686.get_pc_thunk.bx:
+ movl (%esp), %ebx
+ ret
+
+ .text
+ENTRY(strlen)
+ .type strlen, @gnu_indirect_function
+ pushl %ebx
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (ebx, 0)
+ call __i686.get_pc_thunk.bx
+ addl $_GLOBAL_OFFSET_TABLE_, %ebx
+ cmpl $0, KIND_OFFSET+__cpu_features@GOTOFF(%ebx)
+ jne 1f
+ call __init_cpu_features
+1: leal __strlen_ia32@GOTOFF(%ebx), %eax
+ testl $(1<<26), CPUID_OFFSET+COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_EDX_OFFSET+__cpu_features@GOTOFF(%ebx)
+ jz 2f
+ leal __strlen_sse2@GOTOFF(%ebx), %eax
+2: popl %ebx
+ cfi_adjust_cfa_offset (-4);
+ cfi_restore (ebx)
+ ret
+END(strlen)
+
+#define CFI_POP(REG) \
+ cfi_adjust_cfa_offset (-4); \
+ cfi_restore (REG)
+
+#define RETURN popl %esi; CFI_POP (esi); ret
+
+ .text
+ENTRY (__strlen_sse2)
+/*
+ * This implementation uses SSE instructions to compare up to 16 bytes
+ * at a time looking for the end of string (null char).
+ */
+ pushl %esi
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (%esi, 0)
+ mov 8(%esp), %eax
+ mov %eax, %ecx
+ pxor %xmm0, %xmm0 /* 16 null chars */
+ mov %eax, %esi
+ and $15, %ecx
+ jz 1f /* string is 16 byte aligned */
+
+ /*
+ * Unaligned case. Round down to 16-byte boundary before comparing
+ * 16 bytes for a null char. The code then compensates for any extra chars
+ * preceding the start of the string.
+ */
+ and $-16, %esi
+
+ pcmpeqb (%esi), %xmm0
+ lea 16(%eax), %esi
+ pmovmskb %xmm0, %edx
+
+ shr %cl, %edx /* Compensate for bytes preceding the string */
+ test %edx, %edx
+ jnz 2f
+ sub %ecx, %esi /* no null, adjust to next 16-byte boundary */
+ pxor %xmm0, %xmm0 /* clear xmm0, may have been changed... */
+
+ .p2align 4
+1: /* 16 byte aligned */
+ pcmpeqb (%esi), %xmm0 /* look for null bytes */
+ pmovmskb %xmm0, %edx /* move each byte mask of %xmm0 to edx */
+
+ add $16, %esi /* prepare to search next 16 bytes */
+ test %edx, %edx /* if no null byte, %edx must be 0 */
+ jnz 2f /* found a null */
+
+ pcmpeqb (%esi), %xmm0
+ pmovmskb %xmm0, %edx
+ add $16, %esi
+ test %edx, %edx
+ jnz 2f
+
+ pcmpeqb (%esi), %xmm0
+ pmovmskb %xmm0, %edx
+ add $16, %esi
+ test %edx, %edx
+ jnz 2f
+
+ pcmpeqb (%esi), %xmm0
+ pmovmskb %xmm0, %edx
+ add $16, %esi
+ test %edx, %edx
+ jz 1b
+
+2:
+ neg %eax
+ lea -16(%eax, %esi), %eax /* calculate exact offset */
+ bsf %edx, %ecx /* Least significant 1 bit is index of null */
+ add %ecx, %eax
+ popl %esi
+ cfi_adjust_cfa_offset (-4)
+ cfi_restore (%esi)
+ ret
+
+END (__strlen_sse2)
+
+# undef ENTRY
+# define ENTRY(name) \
+ .type __strlen_ia32, @function; \
+ .globl __strlen_ia32; \
+ .p2align 4
+ __strlen_ia32: cfi_startproc; \
+ CALL_MCOUNT
+# undef END
+# define END(name) \
+ cfi_endproc; .size __strlen_ia32, .-__strlen_ia32
+# undef libc_hidden_builtin_def
+/* IFUNC doesn't work with the hidden functions in shared library since
+ they will be called without setting up EBX needed for PLT which is
+ used by IFUNC. */
+# define libc_hidden_builtin_def(name) \
+ .globl __GI_strlen; __GI_strlen = __strlen_ia32
+#endif
+
+#include "../../i586/strlen.S"
diff --git a/sysdeps/i386/i686/multiarch/strspn.S b/sysdeps/i386/i686/multiarch/strspn.S
index 53db131..f11d3ea 100644
--- a/sysdeps/i386/i686/multiarch/strspn.S
+++ b/sysdeps/i386/i686/multiarch/strspn.S
@@ -68,9 +68,9 @@ END(strspn)
# define END(name) \
cfi_endproc; .size __strspn_ia32, .-__strspn_ia32
# undef libc_hidden_builtin_def
-/* It doesn't make sense to send libc-internal strspn calls through a PLT.
- The speedup we get from using SSE4.2 instruction is likely eaten away
- by the indirect call in the PLT. */
+/* IFUNC doesn't work with the hidden functions in shared library since
+ they will be called without setting up EBX needed for PLT which is
+ used by IFUNC. */
# define libc_hidden_builtin_def(name) \
.globl __GI_strspn; __GI_strspn = __strspn_ia32
#endif