[SDK:CRT] Implement memcpy() and wmemcpy()

SDK/CRT/STRING/mem.c

@@ -51,3 +51,35 @@ memcpy (
 
     return ptr;
 }
+
+void *
+memmove (
+    void *dest,
+    const void *src,
+    size_t count
+    )
+
+{
+    void *ptr = dest;
+
+    /* Check for overlap */
+    if (src > dest || ((char *)src + count) < (char *)dest) {
+        /* Low-to-high copy, like memcpy() */
+        while (count--) {
+            *(char *)dest = *(char *)src;
+            dest = (char *)dest + 1;
+            src = (char *)src + 1;
+        }
+    } else {
+        /* High-to-low copy */
+        dest = (char *)dest + count - 1;
+        src = (char *)src + count - 1;
+        while (count--) {
+            *(char *)dest = *(char *)src;
+            dest = (char *)dest - 1;
+            src = (char *)src - 1;
+        }
+    }
+
+    return ptr;
+}