speed up memcpy for aligned bases but misaligned length

1 files changed, 13 insertions, 10 deletions

diff --git a/util/string.c b/util/string.c
index e896379..41855c2 100644
--- a/util/string.c
+++ b/util/string.c
@@ -4,17 +4,20 @@
 
 void* memcpy(void* dest, const void* src, size_t len)
 {
-  if ((((uintptr_t)dest | (uintptr_t)src | len) & (sizeof(uintptr_t)-1)) == 0) {
-    const uintptr_t* s = src;
-    uintptr_t *d = dest;
-    while (d < (uintptr_t*)(dest + len))
-      *d++ = *s++;
-  } else {
-    const char* s = src;
-    char *d = dest;
-    while (d < (char*)(dest + len))
-      *d++ = *s++;
+  const char* s = src;
+  char *d = dest;
+
+  if ((((uintptr_t)dest | (uintptr_t)src) & (sizeof(uintptr_t)-1)) == 0) {
+    while ((void*)d < (dest + len - (sizeof(uintptr_t)-1))) {
+      *(uintptr_t*)d = *(const uintptr_t*)s;
+      d += sizeof(uintptr_t);
+      s += sizeof(uintptr_t);
+    }
   }
+
+  while (d < (char*)(dest + len))
+    *d++ = *s++;
+
   return dest;
 }