Break bionic implementations into arch versions. DO NOT MERGE

Move arch specific code for arm, mips, x86 into separate
makefiles.
In addition, add different arm cpu versions of memcpy/memset.

Bug: 8005082

(cherry picked from commit acdde8c1cf8e8beed98c052757d96695b820b50c)

Change-Id: I0108d432af9f6283ae99adfc92a3399e5ab3e31d
diff --git a/libc/arch-arm/krait/bionic/memset.S b/libc/arch-arm/krait/bionic/memset.S
new file mode 100644
index 0000000..a2e2d80
--- /dev/null
+++ b/libc/arch-arm/krait/bionic/memset.S
@@ -0,0 +1,81 @@
+/*
+ * 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.
+ */
+
+#include <machine/cpu-features.h>
+#include <machine/asm.h>
+
+/*
+ * This code assumes it is running on a processor that supports all arm v7
+ * instructions, that supports neon instructions, and that supports
+ * unaligned neon instruction accesses to memory.
+ */
+
+    .fpu    neon
+
+ENTRY(bzero)
+        mov     r2, r1
+        mov     r1, #0
+END(bzero)
+
+/* memset() returns its first argument.  */
+ENTRY(memset)
+        .save       {r0}
+        stmfd       sp!, {r0}
+
+        vdup.8      q0, r1
+
+        /* make sure we have at least 32 bytes to write */
+        subs        r2, r2, #32
+        blo         2f
+        vmov        q1, q0
+
+1:      /* The main loop writes 32 bytes at a time */
+        subs        r2, r2, #32
+        vst1.8      {d0 - d3}, [r0]!
+        bhs         1b
+
+2:      /* less than 32 left */
+        add         r2, r2, #32
+        tst         r2, #0x10
+        beq         3f
+
+        // writes 16 bytes, 128-bits aligned
+        vst1.8      {d0, d1}, [r0]!
+3:      /* write up to 15-bytes (count in r2) */
+        movs        ip, r2, lsl #29
+        bcc         1f
+        vst1.8      {d0}, [r0]!
+1:      bge         2f
+        vst1.32     {d0[0]}, [r0]!
+2:      movs        ip, r2, lsl #31
+        strmib      r1, [r0], #1
+        strcsb      r1, [r0], #1
+        strcsb      r1, [r0], #1
+        ldmfd       sp!, {r0}
+        bx          lr
+END(memset)