Reorganisation of the source tree

[ghc-hetmet.git] / rts / gmp / mpn / generic / random2.c

diff --git a/rts/gmp/mpn/generic/random2.c b/rts/gmp/mpn/generic/random2.c
new file mode 100644 (file)
index 0000000..86682f8
--- /dev/null
+++ b/rts/gmp/mpn/generic/random2.c
@@ -0,0 +1,105 @@
+/* mpn_random2 -- Generate random numbers with relatively long strings
+   of ones and zeroes.  Suitable for border testing.
+
+Copyright (C) 1992, 1993, 1994, 1996, 2000 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP 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 MP 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 MP 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 "gmp.h"
+#include "gmp-impl.h"
+
+#if defined (__hpux) || defined (__alpha)  || defined (__svr4__) || defined (__SVR4)
+/* HPUX lacks random().  DEC OSF/1 1.2 random() returns a double.  */
+long mrand48 ();
+static inline long
+random ()
+{
+  return mrand48 ();
+}
+#elif defined(_WIN32) && !(defined(__CYGWIN__) || defined(__CYGWIN32__))
+/* MS CRT supplies just the poxy rand(), with an upper bound of 0x7fff */
+static inline unsigned long
+random ()
+{
+  return rand () ^ (rand () << 16) ^ (rand() << 32);
+}
+
+#else
+long random ();
+#endif
+
+/* It's a bit tricky to get this right, so please test the code well
+   if you hack with it.  Some early versions of the function produced
+   random numbers with the leading limb == 0, and some versions never
+   made the most significant bit set.  */
+
+void
+#if __STDC__
+mpn_random2 (mp_ptr res_ptr, mp_size_t size)
+#else
+mpn_random2 (res_ptr, size)
+     mp_ptr res_ptr;
+     mp_size_t size;
+#endif
+{
+  int n_bits;
+  int bit_pos;
+  mp_size_t limb_pos;
+  unsigned int ran;
+  mp_limb_t limb;
+
+  limb = 0;
+
+  /* Start off in a random bit position in the most significant limb.  */
+  bit_pos = random () & (BITS_PER_MP_LIMB - 1);
+
+  /* Least significant bit of RAN chooses string of ones/string of zeroes.
+     Make most significant limb be non-zero by setting bit 0 of RAN.  */
+  ran = random () | 1;
+
+  for (limb_pos = size - 1; limb_pos >= 0; )
+    {
+      n_bits = (ran >> 1) % BITS_PER_MP_LIMB + 1;
+      if ((ran & 1) != 0)
+       {
+         /* Generate a string of ones.  */
+         if (n_bits >= bit_pos)
+           {
+             res_ptr[limb_pos--] = limb | ((((mp_limb_t) 2) << bit_pos) - 1);
+             bit_pos += BITS_PER_MP_LIMB;
+             limb = (~(mp_limb_t) 0) << (bit_pos - n_bits);
+           }
+         else
+           {
+             limb |= ((((mp_limb_t) 1) << n_bits) - 1) << (bit_pos - n_bits + 1);
+           }
+       }
+      else
+       {
+         /* Generate a string of zeroes.  */
+         if (n_bits >= bit_pos)
+           {
+             res_ptr[limb_pos--] = limb;
+             limb = 0;
+             bit_pos += BITS_PER_MP_LIMB;
+           }
+       }
+      bit_pos -= n_bits;
+      ran = random ();
+    }
+}