Optimized strchr and strrchr with SSE2 on x86-32

1 files changed, 159 insertions, 0 deletions

diff --git a/sysdeps/i386/i686/multiarch/strchr-sse2-bsf.S b/sysdeps/i386/i686/multiarch/strchr-sse2-bsf.S
new file mode 100644
index 0000000..5a19ba2
--- /dev/null
+++ b/sysdeps/i386/i686/multiarch/strchr-sse2-bsf.S
@@ -0,0 +1,159 @@
+/* strchr with SSE2 with bsf
+   Copyright (C) 2011 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.  */
+
+#ifndef NOT_IN_libc
+
+# include <sysdep.h>
+
+# define CFI_PUSH(REG)	\
+	cfi_adjust_cfa_offset (4);	\
+	cfi_rel_offset (REG, 0)
+
+# define CFI_POP(REG)	\
+	cfi_adjust_cfa_offset (-4);	\
+	cfi_restore (REG)
+
+# define PUSH(REG) pushl REG; CFI_PUSH (REG)
+# define POP(REG) popl REG; CFI_POP (REG)
+
+# define PARMS  8
+# define ENTRANCE PUSH(%edi)
+# define RETURN  POP(%edi); ret; CFI_PUSH(%edi);
+
+# define STR1  PARMS
+# define STR2  STR1+4
+
+	.text
+ENTRY (__strchr_sse2_bsf)
+
+	ENTRANCE
+	mov	STR1(%esp), %ecx
+	movd	STR2(%esp), %xmm1
+
+	pxor	%xmm2, %xmm2
+	mov	%ecx, %edi
+	punpcklbw %xmm1, %xmm1
+	punpcklbw %xmm1, %xmm1
+	/* ECX has OFFSET. */
+	and	$15, %ecx
+	pshufd	$0, %xmm1, %xmm1
+	je	L(loop)
+
+/* Handle unaligned string.  */
+	and	$-16, %edi
+	movdqa	(%edi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	pcmpeqb	%xmm1, %xmm0
+	/* Find where NULL is.  */
+	pmovmskb %xmm2, %edx
+	/* Check if there is a match.  */
+	pmovmskb %xmm0, %eax
+	/* Remove the leading bytes.  */
+	sarl	%cl, %edx
+	sarl	%cl, %eax
+	test	%eax, %eax
+	je	L(unaligned_no_match)
+	/* Check which byte is a match.  */
+	bsf	%eax, %eax
+	/* Is there a NULL? */
+	test	%edx, %edx
+	je	L(unaligned_match)
+	bsf	%edx, %edx
+	cmpl	%edx, %eax
+	/* Return NULL if NULL comes first.  */
+	ja	L(return_null)
+L(unaligned_match):
+	add	%edi, %eax
+	add	%ecx, %eax
+	RETURN
+
+	.p2align 4
+L(unaligned_no_match):
+	test	%edx, %edx
+	jne	L(return_null)
+	pxor	%xmm2, %xmm2
+
+	add	$16, %edi
+
+	.p2align 4
+/* Loop start on aligned string.  */
+L(loop):
+	movdqa	(%edi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %edi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %edx
+	pmovmskb %xmm0, %eax
+	or	%eax, %edx
+	jnz	L(matches)
+
+	movdqa	(%edi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %edi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %edx
+	pmovmskb %xmm0, %eax
+	or	%eax, %edx
+	jnz	L(matches)
+
+	movdqa	(%edi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %edi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %edx
+	pmovmskb %xmm0, %eax
+	or	%eax, %edx
+	jnz	L(matches)
+
+	movdqa	(%edi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %edi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %edx
+	pmovmskb %xmm0, %eax
+	or	%eax, %edx
+	jnz	L(matches)
+	jmp	L(loop)
+
+L(matches):
+	pmovmskb %xmm2, %edx
+	test	%eax, %eax
+	jz	L(return_null)
+	bsf	%eax, %eax
+	/* There is a match.  First find where NULL is.  */
+	test	%edx, %edx
+	je	L(match)
+	bsf	%edx, %ecx
+	/* Check if NULL comes first.  */
+	cmpl	%ecx, %eax
+	ja	L(return_null)
+L(match):
+	sub	$16, %edi
+	add	%edi, %eax
+	RETURN
+
+/* Return NULL.  */
+	.p2align 4
+L(return_null):
+	xor	%eax, %eax
+	RETURN
+
+END (__strchr_sse2_bsf)
+#endif