fixed bug reported by Joseph Myers

(http://lists.gforge.inria.fr/pipermail/mpc-discuss/2015-April/001342.html)

2 files changed, 16 insertions, 11 deletions

diff --git a/src/exp.c b/src/exp.c
index bc6585b..b28ccea 100644
--- a/src/exp.c
+++ b/src/exp.c
@@ -178,16 +178,16 @@ mpc_exp (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
 
   inex_re = mpfr_set (mpc_realref(rop), y, MPC_RND_RE(rnd));
   inex_im = mpfr_set (mpc_imagref(rop), z, MPC_RND_IM(rnd));
-  if (mpfr_overflow_p ()) {
-    /* overflow in real exponential, inex is sign of infinite result */
-    inex_re = mpc_fix_inf (mpc_realref(rop), MPC_RND_RE(rnd));
-    inex_im = mpc_fix_inf (mpc_imagref(rop), MPC_RND_IM(rnd));
-  }
-  else if (mpfr_underflow_p ()) {
-    /* underflow in real exponential, inex is opposite of sign of 0 result */
-    inex_re = (mpfr_signbit (y) ? +1 : -1);
-    inex_im = (mpfr_signbit (z) ? +1 : -1);
-  }
+  if (mpfr_overflow_p ())
+    {
+      inex_re = mpc_fix_inf (mpc_realref(rop), MPC_RND_RE(rnd));
+      inex_im = mpc_fix_inf (mpc_imagref(rop), MPC_RND_IM(rnd));
+    }
+  else if (mpfr_underflow_p ())
+    {
+      inex_re = mpc_fix_zero (mpc_realref(rop), MPC_RND_RE(rnd));
+      inex_im = mpc_fix_zero (mpc_imagref(rop), MPC_RND_IM(rnd));
+    }
 
   mpfr_clear (x);
   mpfr_clear (y);
diff --git a/tests/exceptions.c b/tests/exceptions.c
index c37a773..257cc65 100644
--- a/tests/exceptions.c
+++ b/tests/exceptions.c
@@ -34,20 +34,25 @@ foo (int f(mpc_ptr, mpc_srcptr, mpc_rnd_t), char *s)
 #define N 5
   mpfr_exp_t exy[N][2] = {{200, 800}, {800, 200}, {-50, 50}, {-10, 1000},
                           {0, 1000}};
-  int n, inex, inex_re, inex_im;
+  int n, inex, inex_re, inex_im, sgn;
 
   mpc_init2 (z, MPFR_PREC_MIN);
   mpc_init2 (t, MPFR_PREC_MIN);
   for (n = 0; n < N; n++)
+    for (sgn = 0; sgn < 4; sgn++)
     {
       if (exy[n][0])
         mpfr_set_ui_2exp (mpc_realref (z), 1, exy[n][0], MPFR_RNDN);
       else
         mpfr_set_ui (mpc_realref (z), 0, MPFR_RNDN);
+      if (sgn & 1)
+        mpfr_neg (mpc_realref (z), mpc_realref (z), MPFR_RNDN);
       if (exy[n][1])
         mpfr_set_ui_2exp (mpc_imagref (z), 1, exy[n][1], MPFR_RNDN);
       else
         mpfr_set_ui (mpc_imagref (z), 0, MPFR_RNDN);
+      if (sgn & 2)
+        mpfr_neg (mpc_imagref (z), mpc_imagref (z), MPFR_RNDN);
 
       inex = f (t, z, MPC_RNDZZ);
       inex_re = MPC_INEX_RE(inex);