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/*
* Copyright (C) 2018 MIPS Tech, LLC
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the copyright holder 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 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 HOLDER 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 <string.h>
#if _MIPS_SIM == _ABIO32
#define SIZEOF_reg_t 4
typedef unsigned long reg_t;
#else
#define SIZEOF_reg_t 8
typedef unsigned long long reg_t;
#endif
typedef struct bits8
{
reg_t B0:8, B1:8, B2:8, B3:8;
#if SIZEOF_reg_t == 8
reg_t B4:8, B5:8, B6:8, B7:8;
#endif
} bits8_t;
typedef struct bits16
{
reg_t B0:16, B1:16;
#if SIZEOF_reg_t == 8
reg_t B2:16, B3:16;
#endif
} bits16_t;
typedef struct bits32
{
reg_t B0:32;
#if SIZEOF_reg_t == 8
reg_t B1:32;
#endif
} bits32_t;
/* This union assumes that small structures can be in registers. If
not, then memory accesses will be done - not optimal, but ok. */
typedef union
{
reg_t v;
bits8_t b8;
bits16_t b16;
bits32_t b32;
} bitfields_t;
/* This code is called when aligning a pointer or there are remaining bytes
after doing word sets. */
static inline void * __attribute__ ((always_inline))
do_bytes (void *a, void *retval, unsigned char fill, const unsigned long len)
{
unsigned char *x = ((unsigned char *) a);
unsigned long i;
for (i = 0; i < len; i++)
*x++ = fill;
return retval;
}
/* Pointer is aligned. */
static void *
do_aligned_words (reg_t * a, void * retval, reg_t fill,
unsigned long words, unsigned long bytes)
{
unsigned long i, words_by_1, words_by_16;
words_by_1 = words % 16;
words_by_16 = words / 16;
/*
* Note: prefetching the store memory is not beneficial on most
* cores since the ls/st unit has store buffers that will be filled
* before the cache line is actually needed.
*
* Also, using prepare-for-store cache op is problematic since we
* don't know the implementation-defined cache line length and we
* don't want to touch unintended memory.
*/
for (i = 0; i < words_by_16; i++)
{
a[0] = fill;
a[1] = fill;
a[2] = fill;
a[3] = fill;
a[4] = fill;
a[5] = fill;
a[6] = fill;
a[7] = fill;
a[8] = fill;
a[9] = fill;
a[10] = fill;
a[11] = fill;
a[12] = fill;
a[13] = fill;
a[14] = fill;
a[15] = fill;
a += 16;
}
/* do remaining words. */
for (i = 0; i < words_by_1; i++)
*a++ = fill;
/* mop up any remaining bytes. */
return do_bytes (a, retval, fill, bytes);
}
void *
memset (void *a, int ifill, size_t len)
{
unsigned long bytes, words;
bitfields_t fill;
void *retval = (void *) a;
/* shouldn't hit that often. */
if (len < 16)
return do_bytes (a, retval, ifill, len);
/* Align the pointer to word/dword alignment.
Note that the pointer is only 32-bits for o32/n32 ABIs. For
n32, loads are done as 64-bit while address remains 32-bit. */
bytes = ((unsigned long) a) % (sizeof (reg_t) * 2);
if (bytes)
{
bytes = (sizeof (reg_t) * 2 - bytes);
if (bytes > len)
bytes = len;
do_bytes (a, retval, ifill, bytes);
if (len == bytes)
return retval;
len -= bytes;
a = (void *) (((unsigned char *) a) + bytes);
}
/* Create correct fill value for reg_t sized variable. */
if (ifill != 0)
{
fill.b8.B0 = (unsigned char) ifill;
fill.b8.B1 = fill.b8.B0;
fill.b16.B1 = fill.b16.B0;
#if SIZEOF_reg_t == 8
fill.b32.B1 = fill.b32.B0;
#endif
}
else
fill.v = 0;
words = len / sizeof (reg_t);
bytes = len % sizeof (reg_t);
return do_aligned_words (a, retval, fill.v, words, bytes);
}
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