log.c: use abs instead of norm to work around intermediate under- and overflow

git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@1211 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 2 insertions, 6 deletions

diff --git a/src/log.c b/src/log.c
index 8c13164..0af4b4e 100644
--- a/src/log.c
+++ b/src/log.c
@@ -141,16 +141,12 @@ do {                                                            \
       prec += mpc_ceil_log2 (prec) + 4;
       mpfr_set_prec (w, prec);
 
-      /* w is rounded down */
-      mpc_norm (w, op, GMP_RNDN);
+      mpc_abs (w, op, GMP_RNDN);
          /* error 0.5 ulp */
-      if (mpfr_inf_p (w) || mpfr_zero_p (w))
-         /* intermediate over- or underflow; the logarithm may be representable */
-         break;
+      MPC_ASSERT (!mpfr_inf_p (w) && !mpfr_zero_p (w));
 
       mpfr_log (w, w, GMP_RNDN);
          /* generic error of log: (2^(- exp(w)) + 0.5) ulp */
-      mpfr_div_2ui (w, w, 1, GMP_RNDN);
 
       err = MPC_MAX (-mpfr_get_exp (w), 0) + 1;
          /* number of lost digits */