mul.c: reverted previous, too hasty commit; needs more thought

mpc-impl.h, mul.c, sqr.c: for the time being, exported mpfr_fmma to be shared
   between mul.c and sqr.c
sqr.dat: added commented out test that currently fails with naive and
   Karatsuba algorithms alike


git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@1135 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 5 insertions, 4 deletions

diff --git a/src/mul.c b/src/mul.c
index 6d64329..842d0ef 100644
--- a/src/mul.c
+++ b/src/mul.c
@@ -171,7 +171,7 @@ mul_imag (mpc_ptr z, mpc_srcptr x, mpc_srcptr y, mpc_rnd_t rnd)
 }
 
 
-static int
+int
 mpfr_fmma (mpfr_ptr z, mpfr_srcptr a, mpfr_srcptr b, mpfr_srcptr c,
            mpfr_srcptr d, int sign, mpfr_rnd_t rnd)
 {
@@ -201,9 +201,10 @@ mpfr_fmma (mpfr_ptr z, mpfr_srcptr a, mpfr_srcptr b, mpfr_srcptr c,
       mpfr_set_si (z, (mpfr_signbit (z) ? -1 : 1), GMP_RNDN);
       inex = mpfr_mul_2ui (z, z, mpfr_get_emax (), rnd);
    }
-   else if (mpfr_inf_p (u) || mpfr_inf_p (v)
-            || mpfr_zero_p (u) || mpfr_zero_p (v)) {
-      /* There is at least one over- or underflow.
+   else if (mpfr_nan_p (z) || (mpfr_zero_p (u) && mpfr_zero_p (v))) {
+      /* In the first case, u and v are infinities with opposite signs.
+         In the second case, u and v are zeroes; their sum may be 0 or the
+         least representable number, with a sign to be determined.
          Redo the computations with mpz_t exponents */
       mpfr_exp_t ea, eb, ec, ed;
       mpz_t eu, ev;