diff --git a/libc/arch-x86_64/string/avx2-wmemset-kbl.S b/libc/arch-x86_64/string/avx2-wmemset-kbl.S
new file mode 100644
index 0000000..7c485cf
--- /dev/null
+++ b/libc/arch-x86_64/string/avx2-wmemset-kbl.S
@@ -0,0 +1,140 @@
+/*
+Copyright (C) 2019 The Android Open Source Project
+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.
+
+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.
+*/
+
+#include <private/bionic_asm.h>
+
+#ifndef WMEMSET
+ #define WMEMSET wmemset_avx2
+#endif
+
+        .section .text.avx2,"ax",@progbits
+
+ENTRY (WMEMSET)
+# BB#0:
+	testq	%rdx, %rdx
+	je	.LBB0_14
+# BB#1:
+	cmpq	$32, %rdx
+	jae	.LBB0_3
+# BB#2:
+	xorl	%r8d, %r8d
+	movq	%rdi, %rax
+	jmp	.LBB0_12
+.LBB0_3:
+	movq	%rdx, %r8
+	andq	$-32, %r8
+	vmovd	%esi, %xmm0
+	vpbroadcastd	%xmm0, %ymm0
+	leaq	-32(%r8), %rcx
+	movq	%rcx, %rax
+	shrq	$5, %rax
+	leal	1(%rax), %r9d
+	andl	$7, %r9d
+	cmpq	$224, %rcx
+	jae	.LBB0_5
+# BB#4:
+	xorl	%eax, %eax
+	testq	%r9, %r9
+	jne	.LBB0_8
+	jmp	.LBB0_10
+.LBB0_5:
+	leaq	992(%rdi), %rcx
+	leaq	-1(%r9), %r10
+	subq	%rax, %r10
+	xorl	%eax, %eax
+	.p2align	4, 0x90
+.LBB0_6:                                # =>This Inner Loop Header: Depth=1
+	vmovdqu	%ymm0, -992(%rcx,%rax,4)
+	vmovdqu	%ymm0, -960(%rcx,%rax,4)
+	vmovdqu	%ymm0, -928(%rcx,%rax,4)
+	vmovdqu	%ymm0, -896(%rcx,%rax,4)
+	vmovdqu	%ymm0, -864(%rcx,%rax,4)
+	vmovdqu	%ymm0, -832(%rcx,%rax,4)
+	vmovdqu	%ymm0, -800(%rcx,%rax,4)
+	vmovdqu	%ymm0, -768(%rcx,%rax,4)
+	vmovdqu	%ymm0, -736(%rcx,%rax,4)
+	vmovdqu	%ymm0, -704(%rcx,%rax,4)
+	vmovdqu	%ymm0, -672(%rcx,%rax,4)
+	vmovdqu	%ymm0, -640(%rcx,%rax,4)
+	vmovdqu	%ymm0, -608(%rcx,%rax,4)
+	vmovdqu	%ymm0, -576(%rcx,%rax,4)
+	vmovdqu	%ymm0, -544(%rcx,%rax,4)
+	vmovdqu	%ymm0, -512(%rcx,%rax,4)
+	vmovdqu	%ymm0, -480(%rcx,%rax,4)
+	vmovdqu	%ymm0, -448(%rcx,%rax,4)
+	vmovdqu	%ymm0, -416(%rcx,%rax,4)
+	vmovdqu	%ymm0, -384(%rcx,%rax,4)
+	vmovdqu	%ymm0, -352(%rcx,%rax,4)
+	vmovdqu	%ymm0, -320(%rcx,%rax,4)
+	vmovdqu	%ymm0, -288(%rcx,%rax,4)
+	vmovdqu	%ymm0, -256(%rcx,%rax,4)
+	vmovdqu	%ymm0, -224(%rcx,%rax,4)
+	vmovdqu	%ymm0, -192(%rcx,%rax,4)
+	vmovdqu	%ymm0, -160(%rcx,%rax,4)
+	vmovdqu	%ymm0, -128(%rcx,%rax,4)
+	vmovdqu	%ymm0, -96(%rcx,%rax,4)
+	vmovdqu	%ymm0, -64(%rcx,%rax,4)
+	vmovdqu	%ymm0, -32(%rcx,%rax,4)
+	vmovdqu	%ymm0, (%rcx,%rax,4)
+	addq	$256, %rax              # imm = 0x100
+	addq	$8, %r10
+	jne	.LBB0_6
+# BB#7:
+	testq	%r9, %r9
+	je	.LBB0_10
+.LBB0_8:
+	leaq	(%rdi,%rax,4), %rax
+	addq	$96, %rax
+	negq	%r9
+	.p2align	4, 0x90
+.LBB0_9:                                # =>This Inner Loop Header: Depth=1
+	vmovdqu	%ymm0, -96(%rax)
+	vmovdqu	%ymm0, -64(%rax)
+	vmovdqu	%ymm0, -32(%rax)
+	vmovdqu	%ymm0, (%rax)
+	subq	$-128, %rax
+	addq	$1, %r9
+	jne	.LBB0_9
+.LBB0_10:
+	cmpq	%rdx, %r8
+	je	.LBB0_14
+# BB#11:
+	leaq	(%rdi,%r8,4), %rax
+.LBB0_12:
+	subq	%r8, %rdx
+	.p2align	4, 0x90
+.LBB0_13:                               # =>This Inner Loop Header: Depth=1
+	movl	%esi, (%rax)
+	addq	$4, %rax
+	addq	$-1, %rdx
+	jne	.LBB0_13
+.LBB0_14:
+	movq	%rdi, %rax
+	vzeroupper
+	retq
+END(WMEMSET)