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/* Copyright (c) 2009 CodeSourcery, Inc.
* 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 CodeSourcery 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 CODESOURCERY, INC. ``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 CODESOURCERY 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 "arm_asm.h"
#include <string.h>
#include <stdint.h>
/* Standard operations for word-sized values. */
#define WORD_REF(ADDRESS, OFFSET) \
*((WORD_TYPE*)((char*)(ADDRESS) + (OFFSET)))
/* On processors with NEON, we use 128-bit vectors. Also,
we need to include arm_neon.h to use these. */
#if defined(__ARM_NEON__)
#include <arm_neon.h>
#define WORD_TYPE uint8x16_t
#define WORD_SIZE 16
#define WORD_DUPLICATE(VALUE) \
vdupq_n_u8(VALUE)
/* On ARM processors with 64-bit ldrd instructions, we use those,
except on Cortex-M* where benchmarking has shown them to
be slower. */
#elif defined(__ARM_ARCH_5E__) || defined(__ARM_ARCH_5TE__) \
|| defined(__ARM_ARCH_5TEJ__) || defined(_ISA_ARM_6)
#define WORD_TYPE uint64_t
#define WORD_SIZE 8
/* ARM stores 64-bit values in two 32-bit registers and does not
have 64-bit multiply or bitwise-or instructions, so this union
operation results in optimal code. */
static inline uint64_t splat8(value) {
union { uint32_t ints[2]; uint64_t result; } quad;
quad.ints[0] = (unsigned char)(value) * 0x01010101;
quad.ints[1] = quad.ints[0];
return quad.result;
}
#define WORD_DUPLICATE(VALUE) \
splat8(VALUE)
/* On everything else, we use 32-bit loads and stores. */
#else
#define WORD_TYPE uint32_t
#define WORD_SIZE 4
#define WORD_DUPLICATE(VALUE) \
(unsigned char)(VALUE) * 0x01010101
#endif
/* On all ARM platforms, 'SHORTWORD' is a 32-bit value. */
#define SHORTWORD_TYPE uint32_t
#define SHORTWORD_SIZE 4
#define SHORTWORD_REF(ADDRESS, OFFSET) \
*((SHORTWORD_TYPE*)((char*)(ADDRESS) + (OFFSET)))
#define SHORTWORD_DUPLICATE(VALUE) \
(uint32_t)(unsigned char)(VALUE) * 0x01010101
void *memset(void *DST, int C, size_t LENGTH)
{
void* DST0 = DST;
unsigned char C_BYTE = C;
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
const char* DST_end = (char*)DST + LENGTH;
while ((char*)DST < DST_end) {
*((char*)DST) = C_BYTE;
DST++;
}
return DST0;
#else /* not PREFER_SIZE_OVER_SPEED */
/* Handle short strings and immediately return. */
if (__builtin_expect(LENGTH < SHORTWORD_SIZE, 1)) {
size_t i = 0;
while (i < LENGTH) {
((char*)DST)[i] = C_BYTE;
i++;
}
return DST;
}
const char* DST_end = (char*)DST + LENGTH;
/* Align DST to SHORTWORD_SIZE. */
while ((uintptr_t)DST % SHORTWORD_SIZE != 0) {
*(char*) (DST++) = C_BYTE;
}
#if WORD_SIZE > SHORTWORD_SIZE
SHORTWORD_TYPE C_SHORTWORD = SHORTWORD_DUPLICATE(C_BYTE);
/* Align DST to WORD_SIZE in steps of SHORTWORD_SIZE. */
if (__builtin_expect(DST_end - (char*)DST >= WORD_SIZE, 0)) {
while ((uintptr_t)DST % WORD_SIZE != 0) {
SHORTWORD_REF(DST, 0) = C_SHORTWORD;
DST += SHORTWORD_SIZE;
}
#endif /* WORD_SIZE > SHORTWORD_SIZE */
WORD_TYPE C_WORD = WORD_DUPLICATE(C_BYTE);
#if defined(__ARM_NEON__)
/* Testing on Cortex-A8 indicates that the following idiom
produces faster assembly code when doing vector copies,
but not when doing regular copies. */
size_t i = 0;
LENGTH = DST_end - (char*)DST;
while (i + WORD_SIZE * 16 <= LENGTH) {
WORD_REF(DST, i) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 1) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 2) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 3) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 4) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 5) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 6) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 7) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 8) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 9) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 10) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 11) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 12) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 13) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 14) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 15) = C_WORD;
i += WORD_SIZE * 16;
}
while (i + WORD_SIZE * 4 <= LENGTH) {
WORD_REF(DST, i) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 1) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 2) = C_WORD;
WORD_REF(DST, i + WORD_SIZE * 3) = C_WORD;
i += WORD_SIZE * 4;
}
while (i + WORD_SIZE <= LENGTH) {
WORD_REF(DST, i) = C_WORD;
i += WORD_SIZE;
}
DST += i;
#else /* not defined(__ARM_NEON__) */
/* Note: 16-times unrolling is about 50% faster than 4-times
unrolling on both ARM Cortex-A8 and Cortex-M3. */
while (DST_end - (char*) DST >= WORD_SIZE * 16) {
WORD_REF(DST, 0) = C_WORD;
WORD_REF(DST, WORD_SIZE * 1) = C_WORD;
WORD_REF(DST, WORD_SIZE * 2) = C_WORD;
WORD_REF(DST, WORD_SIZE * 3) = C_WORD;
WORD_REF(DST, WORD_SIZE * 4) = C_WORD;
WORD_REF(DST, WORD_SIZE * 5) = C_WORD;
WORD_REF(DST, WORD_SIZE * 6) = C_WORD;
WORD_REF(DST, WORD_SIZE * 7) = C_WORD;
WORD_REF(DST, WORD_SIZE * 8) = C_WORD;
WORD_REF(DST, WORD_SIZE * 9) = C_WORD;
WORD_REF(DST, WORD_SIZE * 10) = C_WORD;
WORD_REF(DST, WORD_SIZE * 11) = C_WORD;
WORD_REF(DST, WORD_SIZE * 12) = C_WORD;
WORD_REF(DST, WORD_SIZE * 13) = C_WORD;
WORD_REF(DST, WORD_SIZE * 14) = C_WORD;
WORD_REF(DST, WORD_SIZE * 15) = C_WORD;
DST += WORD_SIZE * 16;
}
while (WORD_SIZE * 4 <= DST_end - (char*) DST) {
WORD_REF(DST, 0) = C_WORD;
WORD_REF(DST, WORD_SIZE * 1) = C_WORD;
WORD_REF(DST, WORD_SIZE * 2) = C_WORD;
WORD_REF(DST, WORD_SIZE * 3) = C_WORD;
DST += WORD_SIZE * 4;
}
while (WORD_SIZE <= DST_end - (char*) DST) {
WORD_REF(DST, 0) = C_WORD;
DST += WORD_SIZE;
}
#endif /* not defined(__ARM_NEON__) */
#if WORD_SIZE > SHORTWORD_SIZE
} /* end if N >= WORD_SIZE */
while (SHORTWORD_SIZE <= DST_end - (char*)DST) {
SHORTWORD_REF(DST, 0) = C_SHORTWORD;
DST += SHORTWORD_SIZE;
}
#endif /* WORD_SIZE > SHORTWORD_SIZE */
while ((char*)DST < DST_end) {
*((char*)DST) = C_BYTE;
DST++;
}
return DST0;
#endif /* not PREFER_SIZE_OVER_SPEED */
}
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