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/* Copyright (C) 2011-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <memcopy.h>
#include <arch/chip.h>
/* How many cache lines ahead should we prefetch? */
#define PREFETCH_LINES_AHEAD 3
void *
__memcpy (void *__restrict dstv, const void *__restrict srcv, size_t n)
{
char *__restrict dst1 = (char *) dstv;
const char *__restrict src1 = (const char *) srcv;
const char *__restrict src1_end;
const char *__restrict prefetch;
op_t *__restrict dst8; /* 8-byte pointer to destination memory. */
op_t final; /* Final bytes to write to trailing word, if any */
long i;
if (n < 16)
{
for (; n; n--)
*dst1++ = *src1++;
return dstv;
}
/* Locate the end of source memory we will copy. Don't prefetch
past this. */
src1_end = src1 + n - 1;
/* Prefetch ahead a few cache lines, but not past the end. */
prefetch = src1;
for (i = 0; i < PREFETCH_LINES_AHEAD; i++)
{
__insn_prefetch (prefetch);
prefetch += CHIP_L2_LINE_SIZE ();
prefetch = (prefetch < src1_end) ? prefetch : src1;
}
/* Copy bytes until dst is word-aligned. */
for (; (uintptr_t) dst1 & (sizeof (op_t) - 1); n--)
*dst1++ = *src1++;
/* 8-byte pointer to destination memory. */
dst8 = (op_t *) dst1;
if (__builtin_expect ((uintptr_t) src1 & (sizeof (op_t) - 1), 0))
{
/* Misaligned copy. Use glibc's _wordcopy_fwd_dest_aligned, but
inline it to avoid prologue/epilogue. TODO: Consider
prefetching and using wh64 as well. */
void * srci;
op_t a0, a1, a2, a3;
long int dstp = (long int) dst1;
long int srcp = (long int) src1;
long int len = n / OPSIZ;
/* Save the initial source pointer so we know the number of
bytes to shift for merging two unaligned results. */
srci = (void *) srcp;
/* Make SRCP aligned by rounding it down to the beginning of the
`op_t' it points in the middle of. */
srcp &= -OPSIZ;
switch (len % 4)
{
case 2:
a1 = ((op_t *) srcp)[0];
a2 = ((op_t *) srcp)[1];
len += 2;
srcp += 2 * OPSIZ;
goto do1;
case 3:
a0 = ((op_t *) srcp)[0];
a1 = ((op_t *) srcp)[1];
len += 1;
srcp += 2 * OPSIZ;
goto do2;
case 0:
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
return dstv;
a3 = ((op_t *) srcp)[0];
a0 = ((op_t *) srcp)[1];
len += 0;
srcp += 2 * OPSIZ;
goto do3;
case 1:
a2 = ((op_t *) srcp)[0];
a3 = ((op_t *) srcp)[1];
srcp += 2 * OPSIZ;
len -= 1;
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
goto do0;
goto do4; /* No-op. */
}
do
{
do4:
a0 = ((op_t *) srcp)[0];
a2 = __insn_dblalign (a2, a3, srci);
((op_t *) dstp)[0] = a2;
srcp += OPSIZ;
dstp += OPSIZ;
do3:
a1 = ((op_t *) srcp)[0];
a3 = __insn_dblalign (a3, a0, srci);
((op_t *) dstp)[0] = a3;
srcp += OPSIZ;
dstp += OPSIZ;
do2:
a2 = ((op_t *) srcp)[0];
a0 = __insn_dblalign (a0, a1, srci);
((op_t *) dstp)[0] = a0;
srcp += OPSIZ;
dstp += OPSIZ;
do1:
a3 = ((op_t *) srcp)[0];
a1 = __insn_dblalign (a1, a2, srci);
((op_t *) dstp)[0] = a1;
srcp += OPSIZ;
dstp += OPSIZ;
len -= 4;
}
while (len != 0);
/* This is the right position for do0. Please don't move
it into the loop. */
do0:
((op_t *) dstp)[0] = __insn_dblalign (a2, a3, srci);
n = n % OPSIZ;
if (n == 0)
return dstv;
a0 = ((const char *) srcp <= src1_end) ? ((op_t *) srcp)[0] : 0;
final = __insn_dblalign (a3, a0, srci);
dst8 = (op_t *)(dstp + OPSIZ);
}
else
{
/* Aligned copy. */
const op_t *__restrict src8 = (const op_t *) src1;
/* src8 and dst8 are both word-aligned. */
if (n >= CHIP_L2_LINE_SIZE ())
{
/* Copy until 'dst' is cache-line-aligned. */
for (; (uintptr_t) dst8 & (CHIP_L2_LINE_SIZE () - 1);
n -= sizeof (op_t))
*dst8++ = *src8++;
for (; n >= CHIP_L2_LINE_SIZE ();)
{
op_t tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
/* Prefetch and advance to next line to prefetch, but
don't go past the end. */
__insn_prefetch (prefetch);
prefetch += CHIP_L2_LINE_SIZE ();
prefetch = (prefetch < src1_end) ? prefetch :
(const char *) src8;
/* Do all the loads before wh64. This is necessary if
[src8, src8+7] and [dst8, dst8+7] share the same
cache line and dst8 <= src8, as can be the case when
called from memmove, or with code tested on x86 whose
memcpy always works with forward copies. */
tmp0 = *src8++;
tmp1 = *src8++;
tmp2 = *src8++;
tmp3 = *src8++;
tmp4 = *src8++;
tmp5 = *src8++;
tmp6 = *src8++;
tmp7 = *src8++;
__insn_wh64 (dst8);
*dst8++ = tmp0;
*dst8++ = tmp1;
*dst8++ = tmp2;
*dst8++ = tmp3;
*dst8++ = tmp4;
*dst8++ = tmp5;
*dst8++ = tmp6;
*dst8++ = tmp7;
n -= 64;
}
#if CHIP_L2_LINE_SIZE() != 64
# error "Fix code that assumes particular L2 cache line size."
#endif
}
for (; n >= sizeof (op_t); n -= sizeof (op_t))
*dst8++ = *src8++;
if (__builtin_expect (n == 0, 1))
return dstv;
final = *src8;
}
/* n != 0 if we get here. Write out any trailing bytes. */
dst1 = (char *) dst8;
#ifndef __BIG_ENDIAN__
if (n & 4)
{
*(uint32_t *) dst1 = final;
dst1 += 4;
final >>= 32;
n &= 3;
}
if (n & 2)
{
*(uint16_t *) dst1 = final;
dst1 += 2;
final >>= 16;
n &= 1;
}
if (n)
*(uint8_t *) dst1 = final;
#else
if (n & 4)
{
*(uint32_t *) dst1 = final >> 32;
dst1 += 4;
}
else
{
final >>= 32;
}
if (n & 2)
{
*(uint16_t *) dst1 = final >> 16;
dst1 += 2;
}
else
{
final >>= 16;
}
if (n & 1)
*(uint8_t *) dst1 = final >> 8;
#endif
return dstv;
}
weak_alias (__memcpy, memcpy)
libc_hidden_builtin_def (memcpy)
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