[src/sub1.c] cancel: also log its value; range checking/tracking.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@13753 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 6 insertions, 1 deletions

diff --git a/src/sub1.c b/src/sub1.c
index 7bb054871..272709acc 100644
--- a/src/sub1.c
+++ b/src/sub1.c
@@ -53,9 +53,10 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
   (void) MPFR_GET_PREC (c);
 
   sign = mpfr_cmp2 (b, c, &cancel);
-  MPFR_LOG_MSG (("sign=%d\n", sign));
+
   if (MPFR_UNLIKELY(sign == 0))
     {
+      MPFR_LOG_MSG (("sign=0\n", 0));
       if (rnd_mode == MPFR_RNDD)
         MPFR_SET_NEG (a);
       else
@@ -64,6 +65,10 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
       MPFR_RET (0);
     }
 
+  /* sign != 0, so that cancel has a valid value. */
+  MPFR_LOG_MSG (("sign=%d cancel=%Pd\n", sign, cancel));
+  MPFR_ASSERTD (cancel >= 0 && cancel <= MPFR_PREC_MAX);
+
   /*
    * If subtraction: sign(a) = sign * sign(b)
    * If addition: sign(a) = sign of the larger argument in absolute value.