Fix problem with long double with ICC (Wrong x86 processor flag).

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@3148 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 29 insertions, 41 deletions

diff --git a/get_ld.c b/get_ld.c
index 459406e15..fed1d56d6 100644
--- a/get_ld.c
+++ b/get_ld.c
@@ -29,59 +29,51 @@ long double
 mpfr_get_ld (mpfr_srcptr x, mp_rnd_t rnd_mode)
 {
 
-  if (!mpfr_number_p (x)) /* NaN or Inf: check before 0.0 */
-    {
-      return (long double) mpfr_get_d (x, rnd_mode);
-    }
-  else if (MPFR_IS_ZERO(x))
-    {
-      return MPFR_SIGN(x) < 0 ? -0.0 : 0.0;
-    }
+  if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
+    return (long double) mpfr_get_d (x, rnd_mode);
   else /* now x is a normal non-zero number */
     {
       long double r; /* result */
       long double m;
       double s; /* part of result */
-      mp_exp_t e; /* exponent of x */
       mp_exp_t sh; /* exponent shift, so that x/2^sh is in the double range */
       mpfr_t y, z;
+      int sign;
 
       /* first round x to the target long double precision, so that
          all subsequent operations are exact (this avoids double rounding
          problems) */
       mpfr_init2 (y, MPFR_LDBL_MANT_DIG);
+      mpfr_init2 (z, IEEE_DBL_MANT_DIG);
+ 
       mpfr_set (y, x, rnd_mode);
-      e = MPFR_GET_EXP (y);
-      if (e > 1023)
-        {
-          sh = e - 1023;
-          MPFR_SET_EXP (y, 1023);
-        }
-      else if (e < -1021)
-        {
-          sh = e + 1021;
-          MPFR_SET_EXP (y, -1021);
-        }
-      else
-        {
-          sh = 0;
-        }
-      /* now -1021 <= e - sh = EXP(y) <= 1023 */
+      sh = MPFR_GET_EXP (y);
+      sign = MPFR_SIGN (y);
+      MPFR_SET_EXP (y, 0);
+      MPFR_SET_POS (y);
+
       r = 0.0;
-      mpfr_init2 (z, IEEE_DBL_MANT_DIG);
+      do {
+	s = mpfr_get_d (y, GMP_RNDN); /* high part of y */
+	r += (long double) s;
+	mpfr_set_d (z, s, GMP_RNDN);  /* exact */
+	mpfr_sub (y, y, z, GMP_RNDN); /* exact */
+      } while (!MPFR_IS_ZERO (y));
 
-      do
-        {
-          s = mpfr_get_d (y, GMP_RNDN); /* high part of y */
-          r += (long double) s;
-          mpfr_set_d (z, s, rnd_mode);  /* exact */
-          mpfr_sub (y, y, z, rnd_mode); /* exact */
-        }
-      while (MPFR_NOTZERO(y));
+      mpfr_clear (z);
+      mpfr_clear (y);
 
       /* we now have to multiply back by 2^sh */
+      MPFR_ASSERTD (r > 0);
       if (sh != 0)
         {
+          /* An overflow may occurs (example: 0.5*2^1024) */
+          while (r < 1.0)
+            {
+              r += r;
+              sh--;
+            }
+
           if (sh > 0)
             m = 2.0;
           else
@@ -89,7 +81,7 @@ mpfr_get_ld (mpfr_srcptr x, mp_rnd_t rnd_mode)
               m = 0.5;
               sh = -sh;
             }
-          e = 1; /* invariant: m = 2^e */
+
           for (;;)
             {
               if (sh % 2)
@@ -98,14 +90,10 @@ mpfr_get_ld (mpfr_srcptr x, mp_rnd_t rnd_mode)
               if (sh == 0)
                 break;
               m = m * m;
-              e = e + e;
             }
         }
-
-      mpfr_clear (z);
-      mpfr_clear (y);
-
+      if (sign < 0)
+	r = -r;
       return r;
     }
-
 }