Macros MPFR_EXP_INVALID (invalid exponent value) and MPFR_EXP_CHECK

added. Code update to use MPFR_GET_EXP and MPFR_SET_EXP instead of
MPFR_EXP to allow more bug detection related to special values.
Macros MPFR_SET_NAN, MPFR_SET_INF, MPFR_SET_ZERO and MPFR_INIT set
the exponent of the number to MPFR_EXP_INVALID if MPFR_EXP_CHECK
is defined. Compile with -DMPFR_EXP_CHECK and make check to see
the potential problems; currently, 40 of 76 tests fail.


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2301 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 15 insertions, 12 deletions

diff --git a/div_2ui.c b/div_2ui.c
index 294ee85ab..94a943239 100644
--- a/div_2ui.c
+++ b/div_2ui.c
@@ -1,6 +1,6 @@
 /* mpfr_div_2ui -- divide a floating-point number by a power of two
 
-Copyright 1999, 2001, 2002 Free Software Foundation, Inc.
+Copyright 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
 
 This file is part of the MPFR Library.
 
@@ -48,18 +48,21 @@ mpfr_div_2ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int n, mp_rnd_t rnd_mode)
       /* MPFR_EMAX_MAX - (long) n is signed and doesn't lead to an integer
          overflow; the first test useful so that the real test can't lead
          to an integer overflow. */
-      if (__gmpfr_emin > MPFR_EMAX_MAX - (long) n ||
-          MPFR_EXP(y) < __gmpfr_emin + (long) n)
-        {
-          if (rnd_mode == GMP_RNDN &&
-              (__gmpfr_emin > MPFR_EMAX_MAX - (long) (n - 1) ||
-               MPFR_EXP(y) < __gmpfr_emin + (long) (n - 1) ||
-               mpfr_powerof2_raw (y)))
-            rnd_mode = GMP_RNDZ;
-          return mpfr_set_underflow (y, rnd_mode, MPFR_SIGN(y));
-        }
+      {
+        mp_exp_t exp = MPFR_GET_EXP (y);
+        if (__gmpfr_emin > MPFR_EMAX_MAX - (long) n ||
+            exp < __gmpfr_emin + (long) n)
+          {
+            if (rnd_mode == GMP_RNDN &&
+                (__gmpfr_emin > MPFR_EMAX_MAX - (long) (n - 1) ||
+                 exp < __gmpfr_emin + (long) (n - 1) ||
+                 mpfr_powerof2_raw (y)))
+              rnd_mode = GMP_RNDZ;
+            return mpfr_set_underflow (y, rnd_mode, MPFR_SIGN(y));
+          }
 
-      MPFR_EXP(y) -= (long) n;
+        MPFR_SET_EXP(y, exp - (long) n);
+      }
     }
 
   return inexact;