Use of MPFR_UNLIKELY and MPFR_IS_SINGULAR for fast detection of special values (Nan, Inf or Zero).

Start to encapsulate the sign to be independant of the reprensation (Must be 1 or -1).


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2525 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 50 insertions, 51 deletions

diff --git a/sub.c b/sub.c
index bdf3b3c20..18e3563fa 100644
--- a/sub.c
+++ b/sub.c
@@ -28,61 +28,60 @@ MA 02111-1307, USA. */
 int
 mpfr_sub (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
 {
-  if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
+  if (MPFR_ARE_SINGULAR(b,c))
     {
-      MPFR_SET_NAN(a);
-      MPFR_RET_NAN;
-    }
-
-  MPFR_CLEAR_NAN(a);
-
-  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 */
-        }
+      if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
+	{
+	  MPFR_SET_NAN(a);
+	  MPFR_RET_NAN;
+	}
+      MPFR_CLEAR_NAN(a);
+      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);
+	      MPFR_RET_NAN;
+	    }
+	}
       else
-        {
-          MPFR_SET_NAN(a);
-          MPFR_RET_NAN;
-        }
-    }
-  else
-    if (MPFR_IS_INF(c))
-      {
-        MPFR_SET_INF(a);
-        if (MPFR_SIGN(c) == MPFR_SIGN(a))
-          MPFR_CHANGE_SIGN(a);
-        MPFR_RET(0); /* exact */
-      }
-
-  MPFR_ASSERTN(MPFR_IS_FP(b) && MPFR_IS_FP(c));
-
-  if (MPFR_IS_ZERO(b))
-    {
+	if (MPFR_IS_INF(c))
+	  {
+	    MPFR_SET_INF(a);
+	    if (MPFR_SIGN(c) == MPFR_SIGN(a))
+	      MPFR_CHANGE_SIGN(a);
+	    MPFR_RET(0); /* exact */
+	  }
+      if (MPFR_IS_ZERO(b))
+	{
+	  if (MPFR_IS_ZERO(c))
+	    {
+	      if (MPFR_SIGN(a) !=
+		  (rnd_mode != GMP_RNDD ?
+		   ((MPFR_SIGN(b) < 0 && MPFR_SIGN(c) > 0) ? -1 : 1) :
+		   ((MPFR_SIGN(b) > 0 && MPFR_SIGN(c) < 0) ? 1 : -1)))
+		MPFR_CHANGE_SIGN(a);
+	      MPFR_CLEAR_INF(a);
+	      MPFR_SET_ZERO(a);
+	      MPFR_RET(0); /* 0 - 0 is exact */
+	    }
+	  return mpfr_neg (a, c, rnd_mode);
+	}
       if (MPFR_IS_ZERO(c))
-        {
-          if (MPFR_SIGN(a) !=
-              (rnd_mode != GMP_RNDD ?
-               ((MPFR_SIGN(b) < 0 && MPFR_SIGN(c) > 0) ? -1 : 1) :
-               ((MPFR_SIGN(b) > 0 && MPFR_SIGN(c) < 0) ? 1 : -1)))
-            MPFR_CHANGE_SIGN(a);
-          MPFR_CLEAR_INF(a);
-          MPFR_SET_ZERO(a);
-          MPFR_RET(0); /* 0 - 0 is exact */
-        }
-      return mpfr_neg (a, c, rnd_mode);
+	{
+	  return mpfr_set (a, b, rnd_mode);
+	}
+      /* Should never reach here */
+      MPFR_ASSERTN(1);
     }
-
-  if (MPFR_IS_ZERO(c))
-    {
-      return mpfr_set (a, b, rnd_mode);
-    }
-
-  MPFR_CLEAR_INF(a);
+  MPFR_CLEAR_FLAGS(a);
+  MPFR_ASSERTD(MPFR_IS_PURE_FP(b) && MPFR_IS_PURE_FP(c));
 
   if (MPFR_SIGN(b) == MPFR_SIGN(c))
     { /* signs are equal, it's a real subtraction */