Unroll 32bit SSE strlen and handle slow bsf

1 files changed, 127 insertions, 0 deletions

diff --git a/sysdeps/i386/i686/multiarch/strlen-sse2-bsf.S b/sysdeps/i386/i686/multiarch/strlen-sse2-bsf.S
new file mode 100644
index 0000000000..0dc651f017
--- /dev/null
+++ b/sysdeps/i386/i686/multiarch/strlen-sse2-bsf.S
@@ -0,0 +1,127 @@
+/* strlen with SSE2 and BSF
+   Copyright (C) 2010 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.  */
+
+#if defined SHARED && !defined NOT_IN_libc
+
+#include <sysdep.h>
+#include "asm-syntax.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		4 + 8	/* Preserve ESI and EDI.  */
+#define	STR		PARMS
+#define ENTRANCE	PUSH (%esi); PUSH (%edi); cfi_remember_state
+#define RETURN		POP (%edi); POP (%esi); ret; \
+			cfi_restore_state; cfi_remember_state
+
+	.text
+ENTRY ( __strlen_sse2_bsf)
+	ENTRANCE
+	mov	STR(%esp), %edi
+	xor	%eax, %eax
+	mov	%edi, %ecx
+	and	$0x3f, %ecx
+	pxor	%xmm0, %xmm0
+	cmp	$0x30, %ecx
+	ja	L(next)
+	movdqu	(%edi), %xmm1
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit_less16)
+	mov	%edi, %eax
+	and	$-16, %eax
+	jmp	L(align16_start)
+L(next):
+
+	mov	%edi, %eax
+	and	$-16, %eax
+	pcmpeqb	(%eax), %xmm0
+	mov	$-1, %esi
+	sub	%eax, %ecx
+	shl	%cl, %esi
+	pmovmskb %xmm0, %edx
+	and	%esi, %edx
+	jnz	L(exit)
+L(align16_start):
+	pxor	%xmm0, %xmm0
+	pxor	%xmm1, %xmm1
+	pxor	%xmm2, %xmm2
+	pxor	%xmm3, %xmm3
+	.p2align 4
+L(align16_loop):
+	pcmpeqb	16(%eax), %xmm0
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%eax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%eax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%eax), %xmm3
+	pmovmskb %xmm3, %edx
+	lea	64(%eax), %eax
+	test	%edx, %edx
+	jz	L(align16_loop)
+L(exit):
+	sub	%edi, %eax
+L(exit_less16):
+	bsf	%edx, %edx
+	add	%edx, %eax
+	RETURN
+L(exit16):
+	sub	%edi, %eax
+	bsf	%edx, %edx
+	add	%edx, %eax
+	add	$16, %eax
+	RETURN
+L(exit32):
+	sub	%edi, %eax
+	bsf	%edx, %edx
+	add	%edx, %eax
+	add	$32, %eax
+	RETURN
+L(exit48):
+	sub	%edi, %eax
+	bsf	%edx, %edx
+	add	%edx, %eax
+	add	$48, %eax
+	POP (%edi)
+	POP (%esi)
+	ret
+
+END ( __strlen_sse2_bsf)
+
+#endif