Imported gcc-4.4.3

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

diff --git a/mpfr/cache.c b/mpfr/cache.c
new file mode 100644 (file)
index 0000000..4c6015f
--- /dev/null
+++ b/mpfr/cache.c
@@ -0,0 +1,126 @@
+/* mpfr_cache -- cache interface for multi-precision const in MPFR.
+
+Copyright 2004, 2005, 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. */
+
+#include "mpfr-impl.h"
+
+void
+mpfr_init_cache (mpfr_cache_t cache, int (*func)(mpfr_ptr, mp_rnd_t))
+{
+  MPFR_PREC (cache->x) = 0; /* Invalid prec to detect that the cache is not
+                               valid. Maybe add a flag? */
+  cache->func = func;
+}
+
+void
+mpfr_clear_cache (mpfr_cache_t cache)
+{
+  if (MPFR_PREC (cache->x) != 0)
+    mpfr_clear (cache->x);
+  MPFR_PREC (cache->x) = 0;
+}
+
+int
+mpfr_cache (mpfr_ptr dest, mpfr_cache_t cache, mp_rnd_t rnd)
+{
+  mp_prec_t prec = MPFR_PREC (dest);
+  mp_prec_t pold = MPFR_PREC (cache->x);
+  int inexact, sign;
+  MPFR_SAVE_EXPO_DECL (expo);
+
+  MPFR_SAVE_EXPO_MARK (expo);
+
+  if (MPFR_UNLIKELY (prec > pold))
+    {
+      /* No previous result in the cache or the precision of the
+         previous result is not sufficient. */
+
+      if (MPFR_UNLIKELY (pold == 0))  /* No previous result. */
+        mpfr_init2 (cache->x, prec);
+
+      /* Update the cache. */
+      pold = prec;
+      mpfr_prec_round (cache->x, pold, GMP_RNDN);
+      cache->inexact = (*cache->func) (cache->x, GMP_RNDN);
+    }
+
+  /* First, check if the cache has the exact value (unlikely).
+     Else the exact value is between (assuming x=cache->x > 0):
+       x and x+ulp(x) if cache->inexact < 0,
+       x-ulp(x) and x if cache->inexact > 0,
+     and abs(x-exact) <= ulp(x)/2. */
+  MPFR_ASSERTN (MPFR_IS_POS (cache->x)); /* TODO... */
+  sign = MPFR_SIGN (cache->x);
+  MPFR_SET_EXP (dest, MPFR_GET_EXP (cache->x));
+  MPFR_SET_SIGN (dest, sign);
+  MPFR_RNDRAW_GEN (inexact, dest,
+                   MPFR_MANT (cache->x), MPFR_PREC (cache->x), rnd, sign,
+                   if (MPFR_UNLIKELY (cache->inexact == 0))
+                     {
+                       if ((_sp[0] & _ulp) == 0)
+                         {
+                           inexact = -sign;
+                           goto trunc_doit;
+                         }
+                       else
+                         goto addoneulp;
+                     }
+                   else if (cache->inexact < 0)
+                     goto addoneulp;
+                   else
+                     {
+                       inexact = -sign;
+                       goto trunc_doit;
+                     },
+                   if (MPFR_UNLIKELY (++MPFR_EXP (dest) > __gmpfr_emax))
+                     mpfr_overflow (dest, rnd, sign);
+                  );
+  if (MPFR_LIKELY (cache->inexact != 0))
+    {
+      switch (rnd)
+        {
+        case GMP_RNDZ:
+        case GMP_RNDD:
+          if (MPFR_UNLIKELY (inexact == 0))
+            {
+              inexact = cache->inexact;
+              if (inexact > 0)
+                mpfr_nextbelow (dest);
+            }
+          break;
+        case GMP_RNDU:
+          if (MPFR_UNLIKELY (inexact == 0))
+            {
+              inexact = cache->inexact;
+              if (inexact < 0)
+                mpfr_nextabove (dest);
+            }
+          break;
+        default: /* GMP_RNDN */
+          if (MPFR_UNLIKELY(inexact == 0))
+            inexact = cache->inexact;
+          break;
+        }
+    }
+
+  MPFR_SAVE_EXPO_FREE (expo);
+  return mpfr_check_range (dest, inexact, rnd);
+}