Merge in an ugly pile of rand* functions from glibc. :(

1 files changed, 59 insertions, 0 deletions

diff --git a/libc/stdlib/drand48-iter.c b/libc/stdlib/drand48-iter.c
new file mode 100644
index 000000000..7ccc2fbc9
--- /dev/null
+++ b/libc/stdlib/drand48-iter.c
@@ -0,0 +1,59 @@
+/* Copyright (C) 1995, 1996, 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu <mailto:drepper@gnu.ai.mit.edu>>, August 1995.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+/* Global state for non-reentrant functions.  */
+struct drand48_data __libc_drand48_data;
+
+
+int
+__drand48_iterate (xsubi, buffer)
+     unsigned short int xsubi[3];
+     struct drand48_data *buffer;
+{
+  uint64_t X;
+  uint64_t result;
+
+  /* Initialize buffer, if not yet done.  */
+  if (unlikely(!buffer->__init))
+    {
+      buffer->__a = 0x5deece66dull;
+      buffer->__c = 0xb;
+      buffer->__init = 1;
+    }
+
+  /* Do the real work.  We choose a data type which contains at least
+     48 bits.  Because we compute the modulus it does not care how
+     many bits really are computed.  */
+
+  X = (uint64_t) xsubi[2] << 32 | (uint32_t) xsubi[1] << 16 | xsubi[0];
+
+  result = X * buffer->__a + buffer->__c;
+
+  xsubi[0] = result & 0xffff;
+  xsubi[1] = (result >> 16) & 0xffff;
+  xsubi[2] = (result >> 32) & 0xffff;
+
+  return 0;
+}