1 files changed, 142 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-3.1.3/src/log2.c b/Build/source/libs/mpfr/mpfr-3.1.3/src/log2.c
new file mode 100644
index 00000000000..4aca0f55753
--- /dev/null
+++ b/Build/source/libs/mpfr/mpfr-3.1.3/src/log2.c
@@ -0,0 +1,142 @@
+/* mpfr_log2 -- log base 2
+
+Copyright 2001-2015 Free Software Foundation, Inc.
+Contributed by the AriC and Caramel 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 3 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.LESSER.  If not, see
+http://www.gnu.org/licenses/ or 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"
+
+ /* The computation of r=log2(a)
+      r=log2(a)=log(a)/log(2)      */
+
+int
+mpfr_log2 (mpfr_ptr r, mpfr_srcptr a, mpfr_rnd_t rnd_mode)
+{
+  int inexact;
+  MPFR_SAVE_EXPO_DECL (expo);
+
+  MPFR_LOG_FUNC
+    (("a[%Pu]=%.*Rg rnd=%d", mpfr_get_prec (a), mpfr_log_prec, a, rnd_mode),
+     ("r[%Pu]=%.*Rg inexact=%d", mpfr_get_prec (r), mpfr_log_prec, r,
+      inexact));
+
+  if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (a)))
+    {
+      /* If a is NaN, the result is NaN */
+      if (MPFR_IS_NAN (a))
+        {
+          MPFR_SET_NAN (r);
+          MPFR_RET_NAN;
+        }
+      /* check for infinity before zero */
+      else if (MPFR_IS_INF (a))
+        {
+          if (MPFR_IS_NEG (a))
+            /* log(-Inf) = NaN */
+            {
+              MPFR_SET_NAN (r);
+              MPFR_RET_NAN;
+            }
+          else /* log(+Inf) = +Inf */
+            {
+              MPFR_SET_INF (r);
+              MPFR_SET_POS (r);
+              MPFR_RET (0);
+            }
+        }
+      else /* a is zero */
+        {
+          MPFR_ASSERTD (MPFR_IS_ZERO (a));
+          MPFR_SET_INF (r);
+          MPFR_SET_NEG (r);
+          mpfr_set_divby0 ();
+          MPFR_RET (0); /* log2(0) is an exact -infinity */
+        }
+    }
+
+  /* If a is negative, the result is NaN */
+  if (MPFR_UNLIKELY (MPFR_IS_NEG (a)))
+    {
+      MPFR_SET_NAN (r);
+      MPFR_RET_NAN;
+    }
+
+  /* If a is 1, the result is 0 */
+  if (MPFR_UNLIKELY (mpfr_cmp_ui (a, 1) == 0))
+    {
+      MPFR_SET_ZERO (r);
+      MPFR_SET_POS (r);
+      MPFR_RET (0); /* only "normal" case where the result is exact */
+    }
+
+  /* If a is 2^N, log2(a) is exact*/
+  if (MPFR_UNLIKELY (mpfr_cmp_ui_2exp (a, 1, MPFR_GET_EXP (a) - 1) == 0))
+    return mpfr_set_si(r, MPFR_GET_EXP (a) - 1, rnd_mode);
+
+  MPFR_SAVE_EXPO_MARK (expo);
+
+  /* General case */
+  {
+    /* Declaration of the intermediary variable */
+    mpfr_t t, tt;
+    /* Declaration of the size variable */
+    mpfr_prec_t Ny = MPFR_PREC(r);              /* target precision */
+    mpfr_prec_t Nt;                             /* working precision */
+    mpfr_exp_t err;                             /* error */
+    MPFR_ZIV_DECL (loop);
+
+    /* compute the precision of intermediary variable */
+    /* the optimal number of bits : see algorithms.tex */
+    Nt = Ny + 3 + MPFR_INT_CEIL_LOG2 (Ny);
+
+    /* initialise of intermediary       variable */
+    mpfr_init2 (t, Nt);
+    mpfr_init2 (tt, Nt);
+
+    /* First computation of log2 */
+    MPFR_ZIV_INIT (loop, Nt);
+    for (;;)
+      {
+        /* compute log2 */
+        mpfr_const_log2(t,MPFR_RNDD); /* log(2) */
+        mpfr_log(tt,a,MPFR_RNDN);     /* log(a) */
+        mpfr_div(t,tt,t,MPFR_RNDN); /* log(a)/log(2) */
+
+        /* estimation of the error */
+        err = Nt-3;
+        if (MPFR_LIKELY (MPFR_CAN_ROUND (t, err, Ny, rnd_mode)))
+          break;
+
+        /* actualisation of the precision */
+        MPFR_ZIV_NEXT (loop, Nt);
+        mpfr_set_prec (t, Nt);
+        mpfr_set_prec (tt, Nt);
+      }
+    MPFR_ZIV_FREE (loop);
+
+    inexact = mpfr_set (r, t, rnd_mode);
+
+    mpfr_clear (t);
+    mpfr_clear (tt);
+  }
+
+  MPFR_SAVE_EXPO_FREE (expo);
+  return mpfr_check_range (r, inexact, rnd_mode);
+}