[src/cmp2.c] Added/updated comments.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@11488 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 4 insertions, 2 deletions

diff --git a/src/cmp2.c b/src/cmp2.c
index 4f5c16a0d..7b58859c7 100644
--- a/src/cmp2.c
+++ b/src/cmp2.c
@@ -85,9 +85,11 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel)
               if (MPFR_LIKELY (cn < 0)) /* |b| = |c| */
                 return 0;
 
+              /* b has been read entirely, but not c. Replace b by c for the
+                 symmetric case below (only the sign differs if not 0). */
               bp = cp;
               bn = cn;
-              cn = -1;
+              cn = -1; /* to enter the following "if" */
               sign = -1;
             }
 
@@ -145,7 +147,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel)
   if (MPFR_LIKELY (diff_exp < GMP_NUMB_BITS))
     {
       cc = cp[cn] >> diff_exp;
-      /* warning: a shift by GMP_NUMB_BITS may give wrong results */
+      /* warning: a shift by GMP_NUMB_BITS is not allowed by ISO C */
       if (diff_exp)
         lastc = cp[cn] << (GMP_NUMB_BITS - diff_exp);
       cn--;