auto import from //depot/cupcake/@135843
diff --git a/libc/arch-arm/bionic/memset.S b/libc/arch-arm/bionic/memset.S
new file mode 100644
index 0000000..d52d622
--- /dev/null
+++ b/libc/arch-arm/bionic/memset.S
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+ .text
+
+ .global memset
+ .type memset, %function
+
+ .global bzero
+ .type bzero, %function
+
+ .align
+
+ /*
+ * Optimized memset() for ARM.
+ *
+ * memset() returns its first argument.
+ */
+
+bzero:
+ mov r2, r1
+ mov r1, #0
+
+memset:
+ /* compute the offset to align the destination
+ * offset = (4-(src&3))&3 = -src & 3
+ */
+ .fnstart
+ .save {r0, r4-r7, lr}
+ stmfd sp!, {r0, r4-r7, lr}
+ rsb r3, r0, #0
+ ands r3, r3, #3
+ cmp r3, r2
+ movhi r3, r2
+
+ /* splat r1 */
+ mov r1, r1, lsl #24
+ orr r1, r1, r1, lsr #8
+ orr r1, r1, r1, lsr #16
+
+ movs r12, r3, lsl #31
+ strcsb r1, [r0], #1 /* can't use strh (alignment unknown) */
+ strcsb r1, [r0], #1
+ strmib r1, [r0], #1
+ subs r2, r2, r3
+ ldmlsfd sp!, {r0, r4-r7, lr} /* return */
+ bxls lr
+
+ /* align the destination to a cache-line */
+ mov r12, r1
+ mov lr, r1
+ mov r4, r1
+ mov r5, r1
+ mov r6, r1
+ mov r7, r1
+
+ rsb r3, r0, #0
+ ands r3, r3, #0x1C
+ beq aligned32
+ cmp r3, r2
+ andhi r3, r2, #0x1C
+ sub r2, r2, r3
+
+ /* conditionnaly writes 0 to 7 words (length in r3) */
+ movs r3, r3, lsl #28
+ stmcsia r0!, {r1, lr}
+ stmcsia r0!, {r1, lr}
+ stmmiia r0!, {r1, lr}
+ movs r3, r3, lsl #2
+ strcs r1, [r0], #4
+
+aligned32:
+ subs r2, r2, #32
+ mov r3, r1
+ bmi 2f
+1: subs r2, r2, #32
+ stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr}
+ bhs 1b
+2: add r2, r2, #32
+
+ /* conditionnaly stores 0 to 31 bytes */
+ movs r2, r2, lsl #28
+ stmcsia r0!, {r1,r3,r12,lr}
+ stmmiia r0!, {r1, lr}
+ movs r2, r2, lsl #2
+ strcs r1, [r0], #4
+ strmih r1, [r0], #2
+ movs r2, r2, lsl #2
+ strcsb r1, [r0]
+ ldmfd sp!, {r0, r4-r7, lr}
+ bx lr
+ .fnend
+