diff --git a/ap/libc/glibc/glibc-2.23/string/testcopy.c b/ap/libc/glibc/glibc-2.23/string/testcopy.c
new file mode 100644
index 0000000..1c9d22b
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/testcopy.c
@@ -0,0 +1,107 @@
+/* Copyright (C) 1990-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <malloc.h>
+
+int
+main (void)
+{
+  char *mem, *memp;
+  char *rand_mem;
+  char *lo_around, *hi_around;
+  int size, max_size;
+  int src_off, dst_off;
+  int i;
+  int space_around = 10;
+
+  max_size = 256;
+
+  mem = malloc (max_size + 2 * max_size + 2 * space_around);
+  rand_mem = malloc (max_size);
+  lo_around = malloc (space_around);
+  hi_around = malloc (space_around);
+  memp = mem + space_around;
+
+  /* Fill RAND_MEM with random bytes, each non-zero.  */
+  for (i = 0; i < max_size; i++)
+    {
+      int x;
+      do
+	x = random ();
+      while (x == 0);
+      rand_mem[i] = x;
+    }
+
+  for (size = 0; size < max_size; size++)
+    {
+      printf("phase %d\n", size);
+      for (src_off = 0; src_off <= 16; src_off++)
+	{
+	  for (dst_off = 0; dst_off <= 16; dst_off++)
+	    {
+	      /* Put zero around the intended destination, to check
+		 that it's not clobbered.  */
+	      for (i = 1; i < space_around; i++)
+		{
+		  memp[dst_off - i] = 0;
+		  memp[dst_off + size - 1 + i] = 0;
+		}
+
+	      /* Fill the source area with known contents.  */
+	      for (i = 0; i < size; i++)
+		memp[src_off + i] = rand_mem[i];
+
+	      /* Remember the contents around the destination area.
+		 (It might not be what we wrote some lines above, since
+		 the src area and the dst area overlap.)  */
+	      for (i = 1; i < space_around; i++)
+		{
+		  lo_around[i] = memp[dst_off - i];
+		  hi_around[i] = memp[dst_off + size - 1 + i];
+		}
+
+	      memmove (memp + dst_off, memp + src_off, size);
+
+	      /* Check that the destination area has the same
+		 contents we wrote to the source area.  */
+	      for (i = 0; i < size; i++)
+		{
+		  if (memp[dst_off + i] != rand_mem[i])
+		    abort ();
+		}
+
+	      /* Check that the area around the destination is not
+		 clobbered.  */
+	      for (i = 1; i < space_around; i++)
+		{
+		  if (memp[dst_off - i] != lo_around[i])
+		    abort ();
+		  if (memp[dst_off + size - 1 + i] != hi_around[i])
+		    abort ();
+		}
+	    }
+	}
+    }
+
+  puts ("Test succeeded.");
+
+  return 0;
+}