djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimize memcpy more

Browse Source
This commit is contained in:
iabdalkader 2014-09-11 19:01:48 +02:00
parent 81b2ddf5d1
commit d60580eb5e
1 changed files with 25 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
stmhal/string0.c
View File

@ -30,14 +30,36 @@
#define likely(x) __builtin_expect((x), 1)
void *memcpy(void *dst, const void *src, size_t n) {
if (likely(!(n&3) && !((long)dst&3) && !((long)src&3))) {
//aligned access, copy words
if (likely(!((long)dst&3) && !((long)src&3))) {
//copy words from aligned pointers first
long *d = dst;
const long *s = src;
for (n=(n>>2); n; n--) {
for (int i=(n>>2); i; i--) {
*d++ = *s++;
}
//copy remaining bytes
if (n&3) {
char *d8 = (char*)d;
const char *s8 =(char*) s;
switch (n&3) {
case 1:
*d8=*s8;
break;
case 2:
*d8++=*s8++;
*d8=*s8;
break;
case 3:
*d8++=*s8++;
*d8++=*s8++;
*d8=*s8;
break;
}
}
} else {
//unaligned access, copy bytes
char *d = dst;