Imported gcc-4.4.3

[msp430-gcc.git] / mpfr / random2.c

diff --git a/mpfr/random2.c b/mpfr/random2.c
new file mode 100644 (file)
index 0000000..e271cd1
--- /dev/null
+++ b/mpfr/random2.c
@@ -0,0 +1,154 @@
+/* mpfr_random2 -- Generate a positive random mpfr_t of specified size, with
+   long runs of consecutive ones and zeros in the binary representation.
+   Intended for testing.
+
+Copyright 1999, 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"
+
+#define LOGBITS_PER_BLOCK 4
+#if GMP_NUMB_BITS < 32
+#define BITS_PER_RANDCALL GMP_NUMB_BITS
+#else
+#define BITS_PER_RANDCALL 32
+#endif
+
+static void
+mpfr_random2_raw (mpfr_ptr x, mp_size_t size, mp_exp_t exp,
+                  gmp_randstate_t rstate)
+{
+  mp_size_t xn, k, ri;
+  unsigned long sh;
+  mp_ptr xp;
+  mp_limb_t elimb, ran, acc;
+  int ran_nbits, bit_pos, nb;
+
+  MPFR_CLEAR_FLAGS (x);
+
+  if (MPFR_UNLIKELY(size == 0))
+    {
+      MPFR_SET_ZERO (x);
+      MPFR_SET_POS (x);
+      return ;
+    }
+  else if (size > 0)
+    {
+      MPFR_SET_POS (x);
+    }
+  else
+    {
+      MPFR_SET_NEG (x);
+      size = -size;
+    }
+
+  xn = MPFR_LIMB_SIZE (x);
+  xp = MPFR_MANT (x);
+  if (size > xn)
+    size = xn;
+  k = xn - size;
+
+  /* Code extracted from GMP, function mpn_random2, to avoid the use
+     of GMP's internal random state in MPFR */
+
+  _gmp_rand (&elimb, rstate, BITS_PER_RANDCALL);
+  ran = elimb;
+
+  /* Start off at a random bit position in the most significant limb.  */
+  bit_pos = GMP_NUMB_BITS - 1;
+  ran >>= 6;                            /* Ideally   log2(GMP_NUMB_BITS) */
+  ran_nbits = BITS_PER_RANDCALL - 6;    /* Ideally - log2(GMP_NUMB_BITS) */
+
+  /* Bit 0 of ran chooses string of ones/string of zeroes.
+     Make most significant limb be non-zero by setting bit 0 of RAN.  */
+  ran |= 1;
+  ri = xn - 1;
+
+  acc = 0;
+  while (ri >= k)
+    {
+      if (ran_nbits < LOGBITS_PER_BLOCK + 1)
+        {
+          _gmp_rand (&elimb, rstate, BITS_PER_RANDCALL);
+          ran = elimb;
+          ran_nbits = BITS_PER_RANDCALL;
+        }
+
+      nb = (ran >> 1) % (1 << LOGBITS_PER_BLOCK) + 1;
+      if ((ran & 1) != 0)
+        {
+          /* Generate a string of nb ones.  */
+          if (nb > bit_pos)
+            {
+              xp[ri--] = acc | (((mp_limb_t) 2 << bit_pos) - 1);
+              bit_pos += GMP_NUMB_BITS;
+              bit_pos -= nb;
+              acc = ((~(mp_limb_t) 1) << bit_pos) & GMP_NUMB_MASK;
+            }
+          else
+            {
+              bit_pos -= nb;
+              acc |= (((mp_limb_t) 2 << nb) - 2) << bit_pos;
+            }
+        }
+      else
+        {
+          /* Generate a string of nb zeroes.  */
+          if (nb > bit_pos)
+            {
+              xp[ri--] = acc;
+              acc = 0;
+              bit_pos += GMP_NUMB_BITS;
+            }
+          bit_pos -= nb;
+        }
+      ran_nbits -= LOGBITS_PER_BLOCK + 1;
+      ran >>= LOGBITS_PER_BLOCK + 1;
+    }
+
+  /* Set mandatory most significant bit.  */
+  /* xp[xn - 1] |= MPFR_LIMB_HIGHBIT; */
+
+  if (k != 0)
+    {
+      /* Clear last limbs */
+      MPN_ZERO (xp, k);
+    }
+  else
+    {
+      /* Mask off non significant bits in the low limb.  */
+      MPFR_UNSIGNED_MINUS_MODULO (sh, MPFR_PREC (x));
+      xp[0] &= ~MPFR_LIMB_MASK (sh);
+    }
+
+  /* Generate random exponent.  */
+  _gmp_rand (&elimb, RANDS, BITS_PER_MP_LIMB);
+  exp = ABS (exp);
+  MPFR_SET_EXP (x, elimb % (2 * exp + 1) - exp);
+
+  return ;
+}
+
+void
+mpfr_random2 (mpfr_ptr x, mp_size_t size, mp_exp_t exp)
+{
+  mpfr_random2_raw (x, size, exp, RANDS);
+}