[U-Boot] [PATCH] Do not copy to same address

Matthias Weisser
2011-04-12T06:58:40Z

In some cases (e.g. bootm with a elf payload) there is a in place copy of
data to the same address. Catching this saves some ms while booting.

Signed-off-by: Matthias Weisser <weisserm@arcor.de>
---
lib/string.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/lib/string.c b/lib/string.c
index b375b81..b8a9203 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -445,6 +445,9 @@ char * bcopy(const char * src, char * dest, int count)
{
char *tmp = dest;

+ if (src == dest)
+ return dest;
+
while (count--)
*tmp++ = *src++;

@@ -467,6 +470,9 @@ void * memcpy(void *dest, const void *src, size_t count)
unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
char *d8, *s8;

+ if (src == dest)
+ return dest;
+
/* while all data is aligned (common case), copy a word at a time */
if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
while (count >= sizeof(*dl)) {
@@ -497,6 +503,9 @@ void * memmove(void * dest,const void *src,size_t count)
{
char *tmp, *s;

+ if (src == dest)
+ return dest;
+
if (dest <= src) {
tmp = (char *) dest;
s = (char *) src;
--
1.7.0.4