--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgcc/memmove.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,20 @@
+/* Public domain.  */
+#include <stddef.h>
+
+void *
+memmove (void *dest, const void *src, size_t len)
+{
+  char *d = dest;
+  const char *s = src;
+  if (d < s)
+    while (len--)
+      *d++ = *s++;
+  else
+    {
+      char *lasts = s + (len-1);
+      char *lastd = d + (len-1);
+      while (len--)
+        *lastd-- = *lasts--;
+    }
+  return dest;
+}