1 files changed, 49 insertions, 0 deletions
diff --git a/stdlib/rand_r.c b/stdlib/rand_r.c
new file mode 100644
index 0000000000..3e0b8b2bc0
--- /dev/null
+++ b/stdlib/rand_r.c
@@ -0,0 +1,49 @@
+/* Reentrant random function frm POSIX.1c.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <stdlib.h>
+
+
+/* This algorithm is mentioned in the ISO C standard, here extended
+   for 32 bits.  */
+int
+rand_r (unsigned int *seed)
+{
+  unsigned int next = *seed;
+  int result;
+
+  next *= 1103515245;
+  next += 12345;
+  result = (unsigned int) (next / 65536) % 2048;
+
+  next *= 1103515245;
+  next += 12345;
+  result <<= 11;
+  result ^= (unsigned int) (next / 65536) % 1024;
+
+  next *= 1103515245;
+  next += 12345;
+  result <<= 10;
+  result ^= (unsigned int) (next / 65536) % 1024;
+
+  *seed = next;
+
+  return result;
+}