From d60580eb5e701853878bcfee34d163ec5746f2a1 Mon Sep 17 00:00:00 2001
From: iabdalkader <i.abdalkader@gmail.com>
Date: Thu, 11 Sep 2014 19:01:48 +0200
Subject: [PATCH] Optimize memcpy more
---
stmhal/string0.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/stmhal/string0.c b/stmhal/string0.c
index 2f28de097..aceca8b68 100644
--- a/stmhal/string0.c
+++ b/stmhal/string0.c
@@ -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;
--
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