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

1 files changed, 48 insertions, 0 deletions

diff --git a/libc/stdlib/erand48_r.c b/libc/stdlib/erand48_r.c
new file mode 100644
index 000000000..fb48304fa
--- /dev/null
+++ b/libc/stdlib/erand48_r.c
@@ -0,0 +1,48 @@
+/* Copyright (C) 1995, 1997, 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 <ieee754.h>
+#include <stdlib.h>
+#include <limits.h>
+
+
+int erand48_r (xsubi, buffer, result)
+     unsigned short int xsubi[3];
+     struct drand48_data *buffer;
+     double *result;
+{
+    union ieee754_double temp;
+
+    /* Compute next state.  */
+    if (__drand48_iterate (xsubi, buffer) < 0)
+	return -1;
+
+    /* Construct a positive double with the 48 random bits distributed over
+       its fractional part so the resulting FP number is [0.0,1.0).  */
+
+    temp.ieee.negative = 0;
+    temp.ieee.exponent = IEEE754_DOUBLE_BIAS;
+    temp.ieee.mantissa0 = (xsubi[2] << 4) | (xsubi[1] >> 12);
+    temp.ieee.mantissa1 = ((xsubi[1] & 0xfff) << 20) | (xsubi[0] << 4);
+
+    /* Please note the lower 4 bits of mantissa1 are always 0.  */
+    *result = temp.d - 1.0;
+
+    return 0;
+}