Imported gcc-4.4.3

[msp430-gcc.git] / mpfr / urandomb.c

diff --git a/mpfr/urandomb.c b/mpfr/urandomb.c
new file mode 100644 (file)
index 0000000..12e9b7b
--- /dev/null
+++ b/mpfr/urandomb.c
@@ -0,0 +1,89 @@
+/* mpfr_urandomb (rop, state, nbits) -- Generate a uniform pseudorandom
+   real number between 0 (inclusive) and 1 (exclusive) of size NBITS,
+   using STATE as the random state previously initialized by a call to
+   gmp_randinit().
+
+Copyright 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+Contributed by the Arenaire and Cacao projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+
+#define MPFR_NEED_LONGLONG_H
+#include "mpfr-impl.h"
+
+int
+mpfr_urandomb (mpfr_ptr rop, gmp_randstate_t rstate)
+{
+  mp_ptr rp;
+  mp_prec_t nbits;
+  mp_size_t nlimbs;
+  mp_size_t k; /* number of high zero limbs */
+  mp_exp_t exp;
+  int cnt;
+
+  MPFR_CLEAR_FLAGS (rop);
+
+  rp = MPFR_MANT (rop);
+  nbits = MPFR_PREC (rop);
+  nlimbs = MPFR_LIMB_SIZE (rop);
+  MPFR_SET_POS (rop);
+
+  /* Uniform non-normalized significand */
+  _gmp_rand (rp, rstate, nlimbs * BITS_PER_MP_LIMB);
+
+  /* If nbits isn't a multiple of BITS_PER_MP_LIMB, mask the low bits */
+  cnt = nlimbs * BITS_PER_MP_LIMB - nbits;
+  if (MPFR_LIKELY (cnt != 0))
+    rp[0] &= ~MPFR_LIMB_MASK (cnt);
+
+  /* Count the null significant limbs and remaining limbs */
+  exp = 0;
+  k = 0;
+  while (nlimbs != 0 && rp[nlimbs - 1] == 0)
+    {
+      k ++;
+      nlimbs --;
+      exp -= BITS_PER_MP_LIMB;
+    }
+
+  if (MPFR_LIKELY (nlimbs != 0)) /* otherwise value is zero */
+    {
+      count_leading_zeros (cnt, rp[nlimbs - 1]);
+      /* Normalization */
+      if (mpfr_set_exp (rop, exp - cnt))
+        {
+          /* If the exponent is not in the current exponent range, we
+             choose to return a NaN as this is probably a user error.
+             Indeed this can happen only if the exponent range has been
+             reduced to a very small interval and/or the precision is
+             huge (very unlikely). */
+          MPFR_SET_NAN (rop);
+          __gmpfr_flags |= MPFR_FLAGS_NAN; /* Can't use MPFR_RET_NAN */
+          return 1;
+        }
+      if (cnt != 0)
+        mpn_lshift (rp + k, rp, nlimbs, cnt);
+      if (k != 0)
+        MPN_ZERO (rp, k);
+    }
+  else
+    MPFR_SET_ZERO (rop);
+
+  return 0;
+}