linux-sg2042/arch/sh64/lib/memcpy.c

82 lines
1.9 KiB
C

/*
* Copyright (C) 2002 Mark Debbage (Mark.Debbage@superh.com)
*
* May be copied or modified under the terms of the GNU General Public
* License. See linux/COPYING for more information.
*
*/
#include <linux/types.h>
#include <asm/string.h>
// This is a simplistic optimization of memcpy to increase the
// granularity of access beyond one byte using aligned
// loads and stores. This is not an optimal implementation
// for SH-5 (especially with regard to prefetching and the cache),
// and a better version should be provided later ...
void *memcpy(void *dest, const void *src, size_t count)
{
char *d = (char *) dest, *s = (char *) src;
if (count >= 32) {
int i = 8 - (((unsigned long) d) & 0x7);
if (i != 8)
while (i-- && count--) {
*d++ = *s++;
}
if (((((unsigned long) d) & 0x7) == 0) &&
((((unsigned long) s) & 0x7) == 0)) {
while (count >= 32) {
unsigned long long t1, t2, t3, t4;
t1 = *(unsigned long long *) (s);
t2 = *(unsigned long long *) (s + 8);
t3 = *(unsigned long long *) (s + 16);
t4 = *(unsigned long long *) (s + 24);
*(unsigned long long *) (d) = t1;
*(unsigned long long *) (d + 8) = t2;
*(unsigned long long *) (d + 16) = t3;
*(unsigned long long *) (d + 24) = t4;
d += 32;
s += 32;
count -= 32;
}
while (count >= 8) {
*(unsigned long long *) d =
*(unsigned long long *) s;
d += 8;
s += 8;
count -= 8;
}
}
if (((((unsigned long) d) & 0x3) == 0) &&
((((unsigned long) s) & 0x3) == 0)) {
while (count >= 4) {
*(unsigned long *) d = *(unsigned long *) s;
d += 4;
s += 4;
count -= 4;
}
}
if (((((unsigned long) d) & 0x1) == 0) &&
((((unsigned long) s) & 0x1) == 0)) {
while (count >= 2) {
*(unsigned short *) d = *(unsigned short *) s;
d += 2;
s += 2;
count -= 2;
}
}
}
while (count--) {
*d++ = *s++;
}
return d;
}