Imported gcc-4.4.3

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

diff --git a/mpfr/sub.c b/mpfr/sub.c
new file mode 100644 (file)
index 0000000..b1454ec
--- /dev/null
+++ b/mpfr/sub.c
@@ -0,0 +1,112 @@
+/* mpfr_sub -- subtract two floating-point numbers
+
+Copyright 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. */
+
+#include "mpfr-impl.h"
+
+int
+mpfr_sub (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
+{
+  MPFR_LOG_FUNC (("b[%#R]=%R c[%#R]=%R rnd=%d", b, b, c, c, rnd_mode),
+                 ("a[%#R]=%R", a, a));
+
+  if (MPFR_ARE_SINGULAR (b,c))
+    {
+      if (MPFR_IS_NAN (b) || MPFR_IS_NAN (c))
+        {
+          MPFR_SET_NAN (a);
+          MPFR_RET_NAN;
+        }
+      else if (MPFR_IS_INF (b))
+        {
+          if (!MPFR_IS_INF (c) || MPFR_SIGN (b) != MPFR_SIGN(c))
+            {
+              MPFR_SET_INF (a);
+              MPFR_SET_SAME_SIGN (a, b);
+              MPFR_RET (0); /* exact */
+            }
+          else
+            {
+              MPFR_SET_NAN (a); /* Inf - Inf */
+              MPFR_RET_NAN;
+            }
+        }
+      else if (MPFR_IS_INF (c))
+        {
+          MPFR_SET_INF (a);
+          MPFR_SET_OPPOSITE_SIGN (a, c);
+          MPFR_RET (0); /* exact */
+        }
+      else if (MPFR_IS_ZERO (b))
+        {
+          if (MPFR_IS_ZERO (c))
+            {
+              int sign = rnd_mode != GMP_RNDD
+                ? ((MPFR_IS_NEG(b) && MPFR_IS_POS(c)) ? -1 : 1)
+                : ((MPFR_IS_POS(b) && MPFR_IS_NEG(c)) ? 1 : -1);
+              MPFR_SET_SIGN (a, sign);
+              MPFR_SET_ZERO (a);
+              MPFR_RET(0); /* 0 - 0 is exact */
+            }
+          else
+            return mpfr_neg (a, c, rnd_mode);
+        }
+      else
+        {
+          MPFR_ASSERTD (MPFR_IS_ZERO (c));
+          return mpfr_set (a, b, rnd_mode);
+        }
+    }
+  MPFR_CLEAR_FLAGS (a);
+  MPFR_ASSERTD (MPFR_IS_PURE_FP (b) && MPFR_IS_PURE_FP (c));
+
+  if (MPFR_LIKELY (MPFR_SIGN (b) == MPFR_SIGN (c)))
+    { /* signs are equal, it's a real subtraction */
+      if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
+                       && MPFR_PREC (b) == MPFR_PREC (c)))
+        return mpfr_sub1sp (a, b, c, rnd_mode);
+      else
+        return mpfr_sub1 (a, b, c, rnd_mode);
+    }
+  else
+    { /* signs differ, it's an addition */
+      if (MPFR_GET_EXP (b) < MPFR_GET_EXP (c))
+         { /* exchange rounding modes towards +/- infinity */
+          int inexact;
+          rnd_mode = MPFR_INVERT_RND (rnd_mode);
+          if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
+                           && MPFR_PREC (b) == MPFR_PREC (c)))
+            inexact = mpfr_add1sp (a, c, b, rnd_mode);
+          else
+            inexact = mpfr_add1 (a, c, b, rnd_mode);
+          MPFR_CHANGE_SIGN (a);
+          return -inexact;
+        }
+      else
+        {
+          if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
+                           && MPFR_PREC (b) == MPFR_PREC (c)))
+            return mpfr_add1sp (a, b, c, rnd_mode);
+          else
+            return mpfr_add1 (a, b, c, rnd_mode);
+        }
+    }
+}