+ Add a new test in case of underflow.

+ Fix bug in case of underflow for sub1 / sub1sp (mpfr_powerof2 could be called with inalid numbers).


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2571 280ebfd0-de03-0410-8827-d642c229c3f4

3 files changed, 8 insertions, 3 deletions

diff --git a/powerof2.c b/powerof2.c
index f549fdfa3..9326d5811 100644
--- a/powerof2.c
+++ b/powerof2.c
@@ -32,7 +32,10 @@ mpfr_powerof2_raw (mpfr_srcptr x)
   mp_limb_t *xp;
   mp_size_t xn;
 
-  MPFR_ASSERTN(MPFR_IS_PURE_FP(x));
+  /* This is an internal function, and we may call it with some
+     wrong numbers (ie good mantissa but wrong flags or exp)
+     So we don't want to test if it is a pure FP.
+     MPFR_ASSERTN(MPFR_IS_PURE_FP(x)); */
   xp = MPFR_MANT(x);
   xn = (MPFR_PREC(x) - 1) / BITS_PER_MP_LIMB;
   if (NOT_POW2(xp[xn]))
diff --git a/sub1sp.c b/sub1sp.c
index 9b4a76d6f..79061872a 100644
--- a/sub1sp.c
+++ b/sub1sp.c
@@ -209,7 +209,7 @@ mpfr_sub1sp (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
 	  if (MPFR_LIKELY(sh))
 	    ap[len] &= ~((MPFR_LIMB_ONE << sh) - MPFR_LIMB_ONE);
 	}
-      /* Check expo overflow */
+      /* Check expo underflow */
       if (MPFR_UNLIKELY(bx < __gmpfr_emin))
 	{
 	  TMP_FREE(marker);
diff --git a/tests/tsub1sp.c b/tests/tsub1sp.c
index 66ee6af64..0be1dd5e8 100644
--- a/tests/tsub1sp.c
+++ b/tests/tsub1sp.c
@@ -346,11 +346,13 @@ void check_special(void)
      if (inexact1 != inexact2)
        STD_ERROR2;
 
+     MPFR_SET_NAN(x);
+     MPFR_SET_NAN(x2);
      mpfr_set_str_binary (y,
       "0.1000000000000000000000000000000000000000000000000000000000000000"
 			  "E-1073741823");
      mpfr_set_str_binary (z,
-      "0.1010000000000000000000000000000000000000000000000000000000000000"
+      "0.1100000000000000000000000000000000000000000000000000000000000000"
 			  "E-1073741823");
      inexact1 = mpfr_sub1(x2, y, z, r);
      inexact2 = mpfr_sub1sp(x, y, z, r);