more changes

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@584 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 3 insertions, 3 deletions

diff --git a/sub.c b/sub.c
index 043a7acb6..7f07e27d1 100644
--- a/sub.c
+++ b/sub.c
@@ -331,13 +331,13 @@ mpfr_sub1(a, b, c, rnd_mode, diff_exp)
 	    kc--;
 	    cc -= mpn_sub_1(&c2, bp+(--k), 1, (cp[kc]>>dif) +
 			    (cp[kc+1]<<(mp_bits_per_limb-dif)));
-	    if (cc==0 || cc==-1) cc=c2;
+	    if (cc==0 || (~cc==0 && ~c2==0)) cc=c2;
 	  }
-	  if ((cc==0 || cc==-1) && kc==0) { 
+	  if ((cc==0 || (~cc==0)) && kc==0) { 
 	    /* it still remains cp[0]<<(mp_bits_per_limb-dif) */
 	    if (k!=0) cc -= mpn_sub_1(&c2, bp+(--k), 1, 
 				      cp[0]<<(mp_bits_per_limb-dif));
-	    else cc -= cp[0]<<(mp_bits_per_limb-dif);
+	    else if (cp[0]<<(mp_bits_per_limb-dif)) cc--;
 	  }
 	  if ((long)cc>0) goto add_one_ulp;
 	  else if ((long)cc<-1) goto end_of_sub; /* carry can be at most 1 */