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/*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU Library General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option) any
* later version.
*
* This program 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 Library General Public License for more
* details.
*/
/* These are carefully optimized mem*() functions for PPC written in C.
* Don't muck around with these function without checking the generated
* assmbler code.
* It is possible to optimize these significantly more by using specific
* data cache instructions(mainly dcbz). However that requires knownledge
* about the CPU's cache line size.
*
* BUG ALERT!
* The cache instructions on MPC8xx CPU's are buggy(they don't update
* the DAR register when causing a DTLB Miss/Error) and cannot be
* used on 8xx CPU's without a kernel patch to work around this
* problem.
*
* Copyright (C) 2004 Joakim Tjernlund
*/
#define _GNU_SOURCE
#include <string.h>
#include <locale.h> /* for __LOCALE_C_ONLY */
#ifdef L_memcpy
void attribute_hidden *__memcpy(void *to, const void *from, size_t n)
/* PPC can do pre increment and load/store, but not post increment and load/store.
Therefore use *++ptr instead of *ptr++. */
{
unsigned long rem, chunks, tmp1, tmp2;
unsigned char *tmp_to;
unsigned char *tmp_from = (unsigned char *)from;
chunks = n / 8;
tmp_from -= 4;
tmp_to = to - 4;
if (!chunks)
goto lessthan8;
rem = (unsigned long )tmp_to % 4;
if (rem)
goto align;
copy_chunks:
do {
/* make gcc to load all data, then store it */
tmp1 = *(unsigned long *)(tmp_from+4);
tmp_from += 8;
tmp2 = *(unsigned long *)tmp_from;
*(unsigned long *)(tmp_to+4) = tmp1;
tmp_to += 8;
*(unsigned long *)tmp_to = tmp2;
} while (--chunks);
lessthan8:
n = n % 8;
if (n >= 4) {
*(unsigned long *)(tmp_to+4) = *(unsigned long *)(tmp_from+4);
tmp_from += 4;
tmp_to += 4;
n = n-4;
}
if (!n ) return to;
tmp_from += 3;
tmp_to += 3;
do {
*++tmp_to = *++tmp_from;
} while (--n);
return to;
align:
rem = 4 - rem;
n = n - rem;
do {
*(tmp_to+4) = *(tmp_from+4);
++tmp_from;
++tmp_to;
} while (--rem);
chunks = n / 8;
if (chunks)
goto copy_chunks;
goto lessthan8;
}
strong_alias(__memcpy, memcpy);
#endif
#ifdef L_memmove
void attribute_hidden *__memmove(void *to, const void *from, size_t n)
{
unsigned long rem, chunks, tmp1, tmp2;
unsigned char *tmp_to;
unsigned char *tmp_from = (unsigned char *)from;
if (tmp_from >= (unsigned char *)to)
return memcpy(to, from, n);
chunks = n / 8;
tmp_from += n;
tmp_to = to + n;
if (!chunks)
goto lessthan8;
rem = (unsigned long )tmp_to % 4;
if (rem)
goto align;
copy_chunks:
do {
/* make gcc to load all data, then store it */
tmp1 = *(unsigned long *)(tmp_from-4);
tmp_from -= 8;
tmp2 = *(unsigned long *)tmp_from;
*(unsigned long *)(tmp_to-4) = tmp1;
tmp_to -= 8;
*(unsigned long *)tmp_to = tmp2;
} while (--chunks);
lessthan8:
n = n % 8;
if (n >= 4) {
*(unsigned long *)(tmp_to-4) = *(unsigned long *)(tmp_from-4);
tmp_from -= 4;
tmp_to -= 4;
n = n-4;
}
if (!n ) return to;
do {
*--tmp_to = *--tmp_from;
} while (--n);
return to;
align:
rem = 4 - rem;
n = n - rem;
do {
*--tmp_to = *--tmp_from;
} while (--rem);
chunks = n / 8;
if (chunks)
goto copy_chunks;
goto lessthan8;
}
strong_alias(__memmove, memmove);
#endif
#ifdef L_memset
static inline int expand_byte_word(int c){
/* this does:
c = c << 8 | c;
c = c << 16 | c ;
*/
asm("rlwimi %0,%0,8,16,23\n"
"\trlwimi %0,%0,16,0,15\n"
: "=r" (c) : "0" (c));
return c;
}
void attribute_hidden *__memset(void *to, int c, size_t n)
{
unsigned long rem, chunks;
unsigned char *tmp_to;
chunks = n / 8;
tmp_to = to - 4;
c = expand_byte_word(c);
if (!chunks)
goto lessthan8;
rem = (unsigned long )tmp_to % 4;
if (rem)
goto align;
copy_chunks:
do {
*(unsigned long *)(tmp_to+4) = c;
tmp_to += 4;
*(unsigned long *)(tmp_to+4) = c;
tmp_to += 4;
} while (--chunks);
lessthan8:
n = n % 8;
if (n >= 4) {
*(unsigned long *)(tmp_to+4) = c;
tmp_to += 4;
n = n-4;
}
if (!n ) return to;
tmp_to += 3;
do {
*++tmp_to = c;
} while (--n);
return to;
align:
rem = 4 - rem;
n = n-rem;
do {
*(tmp_to+4) = c;
++tmp_to;
} while (--rem);
chunks = n / 8;
if (chunks)
goto copy_chunks;
goto lessthan8;
}
strong_alias(__memset, memset);
#endif
#ifdef L_bzero
weak_alias(__bzero,bzero);
void __bzero(void *s, size_t n)
{
(void)memset(s, 0, n);
}
#endif
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