diff --git a/libc/arch-x86_64/string/sse2-strlen-slm.S b/libc/arch-x86_64/string/sse2-strlen-slm.S
new file mode 100644
index 0000000..3772fe7
--- /dev/null
+++ b/libc/arch-x86_64/string/sse2-strlen-slm.S
@@ -0,0 +1,294 @@
+/*
+Copyright (c) 2014, Intel Corporation
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice,
+    * this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+    * this list of conditions and the following disclaimer in the documentation
+    * and/or other materials provided with the distribution.
+
+    * Neither the name of Intel Corporation nor the names of its contributors
+    * may be used to endorse or promote products derived from this software
+    * without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef USE_AS_STRCAT
+
+#ifndef STRLEN
+# define STRLEN		strlen
+#endif
+
+#ifndef L
+# define L(label)	.L##label
+#endif
+
+#ifndef cfi_startproc
+# define cfi_startproc			.cfi_startproc
+#endif
+
+#ifndef cfi_endproc
+# define cfi_endproc			.cfi_endproc
+#endif
+
+#ifndef ENTRY
+# define ENTRY(name)			\
+	.type name,  @function; 	\
+	.globl name;			\
+	.p2align 4;			\
+name:					\
+	cfi_startproc
+#endif
+
+#ifndef END
+# define END(name)			\
+	cfi_endproc;			\
+	.size name, .-name
+#endif
+#define RETURN ret
+	.section .text.sse2,"ax",@progbits
+ENTRY (STRLEN)
+/* end ifndef USE_AS_STRCAT */
+#endif
+	xor	%rax, %rax
+	mov	%edi, %ecx
+	and	$0x3f, %ecx
+	pxor	%xmm0, %xmm0
+	cmp	$0x30, %ecx
+	ja	L(next)
+	movdqu	(%rdi), %xmm1
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit_less16)
+	mov	%rdi, %rax
+	and	$-16, %rax
+	jmp	L(align16_start)
+L(next):
+	mov	%rdi, %rax
+	and	$-16, %rax
+	pcmpeqb	(%rax), %xmm0
+	mov	$-1, %r10d
+	sub	%rax, %rcx
+	shl	%cl, %r10d
+	pmovmskb %xmm0, %edx
+	and	%r10d, %edx
+	jnz	L(exit)
+L(align16_start):
+	pxor	%xmm0, %xmm0
+	pxor	%xmm1, %xmm1
+	pxor	%xmm2, %xmm2
+	pxor	%xmm3, %xmm3
+	pcmpeqb	16(%rax), %xmm0
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	test	%edx, %edx
+	jnz	L(exit64)
+
+	pcmpeqb	80(%rax), %xmm0
+	add	$64, %rax
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	test	%edx, %edx
+	jnz	L(exit64)
+
+	pcmpeqb	80(%rax), %xmm0
+	add	$64, %rax
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	test	%edx, %edx
+	jnz	L(exit64)
+	
+	pcmpeqb	80(%rax), %xmm0
+	add	$64, %rax
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	test	%edx, %edx
+	jnz	L(exit64)
+	
+
+	test	$0x3f, %rax
+	jz	L(align64_loop)
+
+	pcmpeqb	80(%rax), %xmm0
+	add	$80, %rax
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit)
+
+	test	$0x3f, %rax
+	jz	L(align64_loop)
+
+	pcmpeqb	16(%rax), %xmm1
+	add	$16, %rax
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit)
+
+	test	$0x3f, %rax
+	jz	L(align64_loop)
+
+	pcmpeqb	16(%rax), %xmm2
+	add	$16, %rax
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit)
+
+	test	$0x3f, %rax
+	jz	L(align64_loop)
+
+	pcmpeqb	16(%rax), %xmm3
+	add	$16, %rax
+	pmovmskb %xmm3, %edx
+	test	%edx, %edx
+	jnz	L(exit)
+
+	add	$16, %rax
+	.p2align 4
+	L(align64_loop):
+	movaps	(%rax),	%xmm4
+	pminub	16(%rax), 	%xmm4
+	movaps	32(%rax), 	%xmm5
+	pminub	48(%rax), 	%xmm5
+	add	$64, 	%rax
+	pminub	%xmm4,	%xmm5
+	pcmpeqb	%xmm0,	%xmm5
+	pmovmskb %xmm5,	%edx
+	test	%edx,	%edx
+	jz	L(align64_loop)
+
+
+	pcmpeqb	-64(%rax), %xmm0
+	sub	$80, 	%rax
+	pmovmskb %xmm0, %edx
+	test	%edx, %edx
+	jnz	L(exit16)
+
+	pcmpeqb	32(%rax), %xmm1
+	pmovmskb %xmm1, %edx
+	test	%edx, %edx
+	jnz	L(exit32)
+
+	pcmpeqb	48(%rax), %xmm2
+	pmovmskb %xmm2, %edx
+	test	%edx, %edx
+	jnz	L(exit48)
+
+	pcmpeqb	64(%rax), %xmm3
+	pmovmskb %xmm3, %edx
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	add	$64, %rax
+	RETURN
+
+	.p2align 4
+L(exit):
+	sub	%rdi, %rax
+L(exit_less16):
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	RETURN
+	.p2align 4
+L(exit16):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	add	$16, %rax
+	RETURN
+	.p2align 4
+L(exit32):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	add	$32, %rax
+	RETURN
+	.p2align 4
+L(exit48):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	add	$48, %rax
+	RETURN
+	.p2align 4
+L(exit64):
+	sub	%rdi, %rax
+	bsf	%rdx, %rdx
+	add	%rdx, %rax
+	add	$64, %rax
+#ifndef USE_AS_STRCAT
+	RETURN
+
+END (STRLEN)
+#endif