Revert " * sysdeps/x86_64/strlen.S: Replace with new SSE2 based implementation"

This reverts commit b79188d71716b6286866e06add976fe84100595e.

1 files changed, 65 insertions, 198 deletions

diff --git a/sysdeps/x86_64/strlen.S b/sysdeps/x86_64/strlen.S
index e82fe8d039..4bdca0a452 100644
--- a/sysdeps/x86_64/strlen.S
+++ b/sysdeps/x86_64/strlen.S
@@ -1,5 +1,6 @@
-/* SSE2 version of strlen.
-   Copyright (C) 2012, 2013 Free Software Foundation, Inc.
+/* strlen(str) -- determine the length of the string STR.
+   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
@@ -18,217 +19,83 @@
 
 #include <sysdep.h>
 
-/* Long lived register are
-	strlen(s), strnlen(s, n):
 
-	%xmm11 - zero
-	%rdi   - s
-	%r10  (s+n)	& (~(64-1))
-	%r11   s+n
-*/
-
-
-.text
+	.text
 ENTRY(strlen)
-
-#define FIND_ZERO	\
-	pcmpeqb	(%rax), %xmm8;	\
-	pcmpeqb	16(%rax), %xmm9;	\
-	pcmpeqb	32(%rax), %xmm10;	\
-	pcmpeqb	48(%rax), %xmm11;	\
-	pmovmskb	%xmm8, %esi;	\
-	pmovmskb	%xmm9, %edx;	\
-	pmovmskb	%xmm10, %r8d;	\
-	pmovmskb	%xmm11, %ecx;	\
-	salq	$16, %rdx;	\
-	salq	$16, %rcx;	\
-	orq	%rsi, %rdx;	\
-	orq	%r8, %rcx;	\
-	salq	$32, %rcx;	\
-	orq	%rcx, %rdx;
-
-#ifdef AS_STRNLEN
-/* Do not read anything when n==0.  */
-	test	%rsi, %rsi
-	jne	L(n_nonzero)
 	xor	%rax, %rax
-	ret
-L(n_nonzero):
-
-/* Initialize long lived registers.  */
-
-	add	%rdi, %rsi
-	mov	%rsi, %r10
-	and	$-64, %r10
-	mov	%rsi, %r11
-#endif
-
-	pxor	%xmm8, %xmm8
-	pxor	%xmm9, %xmm9
-	pxor	%xmm10, %xmm10
-	pxor	%xmm11, %xmm11
-	movq	%rdi, %rax
-	movq	%rdi, %rcx
-	andq	$4095, %rcx
-/* Offsets 4032-4047 will be aligned into 4032 thus fit into page.  */
-	cmpq	$4047, %rcx
-/* We cannot unify this branching as it would be ~6 cycles slower.  */
+	mov	%edi, %ecx
+	and	$0x3f, %ecx
+	pxor	%xmm0, %xmm0
+	cmp	$0x30, %ecx
 	ja	L(next)
-
-#ifdef AS_STRNLEN
-# define STRNLEN_PROLOG	\
-	mov	%r11, %rsi;	\
-	subq	%rax, %rsi;	\
-	andq	$-64, %rax;	\
-	testq	$-64, %rsi;	\
-	je	L(strnlen_ret)
-#else
-# define STRNLEN_PROLOG  andq $-64, %rax;
-#endif
-
-#define PROLOG(lab)	\
-	movq	%rdi, %rcx;	\
-	xorq	%rax, %rcx;	\
-	STRNLEN_PROLOG;	\
-	sarq	%cl, %rdx;	\
-	test	%rdx, %rdx;	\
-	je	L(lab);	\
-	bsfq	%rdx, %rax;	\
-	ret
-
-#ifdef AS_STRNLEN
-	andq	$-16, %rax
-	FIND_ZERO
-#else
-	movdqu	(%rax), %xmm12
-	pcmpeqb	%xmm8, %xmm12
-	pmovmskb	%xmm12, %edx
+	movdqu	(%rdi), %xmm1
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm0, %edx
 	test	%edx, %edx
-	je 	L(next48_bytes)
-	bsfq	%rdx, %rax
-	ret
-
-L(next48_bytes):
-/* Same as FIND_ZERO except we do not check first 16 bytes.  */
-	andq	$-16, %rax
-	pcmpeqb 16(%rax), %xmm9;
-	pcmpeqb 32(%rax), %xmm10;
-	pcmpeqb 48(%rax), %xmm11;
-	pmovmskb	%xmm9, %edx;
-	pmovmskb	%xmm10, %r8d;
-	pmovmskb	%xmm11, %ecx;
-	salq	$16, %rdx;
-	salq	$16, %rcx;
-	orq	%r8, %rcx;
-	salq	$32, %rcx;
-	orq	%rcx, %rdx;
-#endif
-
-	PROLOG(loop)
-
-	.p2align 4
+	jnz	L(exit_less16)
+	mov	%rdi, %rax
+	and	$-16, %rax
+	jmp	L(align16_start)
 L(next):
-	andq	$-64, %rax
-	FIND_ZERO
-	PROLOG(loop_init)
-
-#ifdef AS_STRNLEN
-/* We must do this check to correctly handle strnlen (s, -1).  */
-L(strnlen_ret):
-	bts	%rsi, %rdx
-	sarq	%cl, %rdx
-	test	%rdx, %rdx
-	je	L(loop_init)
-	bsfq	%rdx, %rax
-	ret
-#endif
-	.p2align 4
-L(loop_init):
-	pxor	%xmm9, %xmm9
-	pxor	%xmm10, %xmm10
-	pxor	%xmm11, %xmm11
-#ifdef AS_STRNLEN
+	mov	%rdi, %rax
+	and	$-16, %rax
+	pcmpeqb	(%rax), %xmm0
+	mov	$-1, %esi
+	sub	%rax, %rcx
+	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(loop):
-
-	addq	$64, %rax
-	cmpq	%rax, %r10
-	je	L(exit_end)
+L(align16_loop):
+	pcmpeqb	16(%rax), %xmm0
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
 
-	movdqa	(%rax), %xmm8
-	pminub	16(%rax), %xmm8
-	pminub	32(%rax), %xmm8
-	pminub	48(%rax), %xmm8
-	pcmpeqb	%xmm11, %xmm8
-	pmovmskb	%xmm8, %edx
-	testl	%edx, %edx
-	jne	L(exit)
-	jmp	L(loop)
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
 
-	.p2align 4
-L(exit_end):
-	cmp	%rax, %r11
-	je	L(first)
-	pxor	%xmm8, %xmm8
-	FIND_ZERO
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
 
-L(first):
-	bts	%r11, %rdx
-	bsfq	%rdx, %rdx
-	addq	%rdx, %rax
-	subq	%rdi, %rax
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	lea	64(%rax), %rax
+	test	%edx, %edx
+	jz	L(align16_loop)
+L(exit):
+	sub	%rdi, %rax
+L(exit_less16):
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
 	ret
-
 	.p2align 4
-L(exit):
-	pxor	%xmm8, %xmm8
-	FIND_ZERO
-
-	bsfq	%rdx, %rdx
-	addq	%rdx, %rax
-	subq	%rdi, %rax
+L(exit16):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	lea	16(%rdx,%rax), %rax
 	ret
-
-#else
 	.p2align 4
-L(loop):
-
-	movdqa	64(%rax), %xmm8
-	pminub	80(%rax), %xmm8
-	pminub	96(%rax), %xmm8
-	pminub	112(%rax), %xmm8
-	pcmpeqb	%xmm11, %xmm8
-	pmovmskb	%xmm8, %edx
-	testl	%edx, %edx
-	jne	L(exit64)
-
-	subq	$-128, %rax
-
-	movdqa	(%rax), %xmm8
-	pminub	16(%rax), %xmm8
-	pminub	32(%rax), %xmm8
-	pminub	48(%rax), %xmm8
-	pcmpeqb	%xmm11, %xmm8
-	pmovmskb	%xmm8, %edx
-	testl	%edx, %edx
-	jne	L(exit0)
-	jmp	L(loop)
-
+L(exit32):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	lea	32(%rdx,%rax), %rax
+	ret
 	.p2align 4
-L(exit64):
-	addq	$64, %rax
-L(exit0):
-	pxor	%xmm8, %xmm8
-	FIND_ZERO
-
-	bsfq	%rdx, %rdx
-	addq	%rdx, %rax
-	subq	%rdi, %rax
+L(exit48):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	lea	48(%rdx,%rax), %rax
 	ret
-
-#endif
-
 END(strlen)
-#ifndef AS_STRLEN
 libc_hidden_builtin_def (strlen)
-#endif