add 32-bit bionic implementation for denver arch

Add 32-bit bionic implementation for denver. Use denver version of memcpy/
memset. Use Cortex-A15 version of strlen/strcat/strcpy/strcmp.

Change-Id: I4c6b675f20cf41a29cadf70a11d1635d7df5b30a
diff --git a/libc/arch-arm/denver/bionic/memset.S b/libc/arch-arm/denver/bionic/memset.S
new file mode 100644
index 0000000..bf3d9ad
--- /dev/null
+++ b/libc/arch-arm/denver/bionic/memset.S
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
+ * 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 <private/bionic_asm.h>
+#include <private/libc_events.h>
+
+        /*
+         * Optimized memset() for ARM.
+         *
+         * memset() returns its first argument.
+         */
+
+        .fpu        neon
+        .syntax     unified
+
+ENTRY(__memset_chk)
+        cmp         r2, r3
+        bls         .L_done
+
+        // Preserve lr for backtrace.
+        push        {lr}
+        .cfi_def_cfa_offset 4
+        .cfi_rel_offset lr, 0
+
+
+        ldr         r0, error_message
+        ldr         r1, error_code
+1:
+        add         r0, pc
+        bl          __fortify_chk_fail
+error_code:
+        .word       BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW
+error_message:
+        .word       error_string-(1b+8)
+END(__memset_chk)
+
+ENTRY(bzero)
+        mov         r2, r1
+        mov         r1, #0
+.L_done:
+        // Fall through to memset...
+END(bzero)
+
+ENTRY(memset)
+        pldw        [r0]
+        mov         r3, r0
+
+        // Duplicate the low byte of r1
+        mov         r1, r1, lsl #24
+        orr         r1, r1, r1, lsr #8
+        orr         r1, r1, r1, lsr #16
+
+        cmp         r2, #16
+        blo         .L_less_than_16
+
+        // This section handles regions 16 bytes or larger
+        //
+        // Use aligned vst1.8 and vstm when possible.  Register values will be:
+        //   ip is scratch
+        //   q0, q1, and r1 contain the memset value
+        //   r2 is the number of bytes to set
+        //   r3 is the advancing destination pointer
+        vdup.32     q0, r1
+
+        ands        ip, r3, 0xF
+        beq         .L_memset_aligned
+
+        // Align dest pointer to 16-byte boundary.
+        pldw        [r0, #64]
+        rsb         ip, ip, #16
+
+        // Pre-adjust the byte count to reflect post-aligment value.  Expecting
+        // 8-byte alignment to be rather common so we special case that one.
+        sub         r2, r2, ip
+
+        /* set 1 byte */
+        tst         ip, #1
+        it          ne
+        strbne      r1, [r3], #1
+        /* set 2 bytes */
+        tst         ip, #2
+        it          ne
+        strhne      r1, [r3], #2
+        /* set 4 bytes */
+        movs        ip, ip, lsl #29
+        it          mi
+        strmi       r1, [r3], #4
+        /* set 8 bytes */
+        itt         cs
+        strcs       r1, [r3], #4
+        strcs       r1, [r3], #4
+
+.L_memset_aligned:
+        // Destination is now 16-byte aligned.  Determine how to handle
+        // remaining bytes.
+        vmov        q1, q0
+        cmp         r2, #128
+        blo         .L_less_than_128
+
+        // We need to set a larger block of memory.  Use four Q regs to
+        // set a full cache line in one instruction.  Pre-decrement
+        // r2 to simplify end-of-loop detection
+        vmov        q2, q0
+        vmov        q3, q0
+        pldw        [r0, #128]
+        sub         r2, r2, #128
+        .align 4
+.L_memset_loop_128:
+        pldw        [r3, #192]
+        vstm        r3!, {q0, q1, q2, q3}
+        vstm        r3!, {q0, q1, q2, q3}
+        subs        r2, r2, #128
+        bhs         .L_memset_loop_128
+
+        // Un-bias r2 so it contains the number of bytes left.  Early
+        // exit if we are done.
+        adds        r2, r2, #128
+        beq         2f
+
+        .align 4
+.L_less_than_128:
+        // set 64 bytes
+        movs        ip, r2, lsl #26
+        bcc         1f
+        vst1.8      {q0, q1}, [r3, :128]!
+        vst1.8      {q0, q1}, [r3, :128]!
+        beq         2f
+1:
+        // set 32 bytes
+        bpl         1f
+        vst1.8      {q0, q1}, [r3, :128]!
+1:
+        // set 16 bytes
+        movs        ip, r2, lsl #28
+        bcc         1f
+        vst1.8      {q0}, [r3, :128]!
+        beq         2f
+1:
+        // set 8 bytes
+        bpl         1f
+        vst1.8      {d0}, [r3, :64]!
+1:
+        // set 4 bytes
+        tst         r2, #4
+        it          ne
+        strne       r1, [r3], #4
+1:
+        // set 2 bytes
+        movs        ip, r2, lsl #31
+        it          cs
+        strhcs      r1, [r3], #2
+        // set 1 byte
+        it          mi
+        strbmi      r1, [r3]
+2:
+        bx          lr
+
+.L_less_than_16:
+        // Store up to 15 bytes without worrying about byte alignment
+        movs        ip, r2, lsl #29
+        bcc         1f
+        str         r1, [r3], #4
+        str         r1, [r3], #4
+        beq         2f
+1:
+        it          mi
+        strmi       r1, [r3], #4
+        movs        ip, r2, lsl #31
+        it          mi
+        strbmi      r1, [r3], #1
+        itt         cs
+        strbcs      r1, [r3], #1
+        strbcs      r1, [r3]
+2:
+        bx          lr
+END(memset)
+
+        .data
+error_string:
+        .string     "memset: prevented write past end of buffer"