diff options
Diffstat (limited to 'src/sub1.c')
| -rw-r--r-- | src/sub1.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/src/sub1.c b/src/sub1.c index 8ff8e3061..755042a73 100644 --- a/src/sub1.c +++ b/src/sub1.c @@ -28,8 +28,6 @@ https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., a positive value otherwise. */ -/* TODO: check the code in case exp_b == MPFR_EXP_MAX. */ - int mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode) { @@ -55,6 +53,7 @@ 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)) { if (rnd_mode == MPFR_RNDD) @@ -94,6 +93,15 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode) exp_b = MPFR_IS_UBF (b) ? mpfr_ubf_zexp2exp (MPFR_ZEXP (b)) : MPFR_GET_EXP (b); diff_exp = mpfr_ubf_diff_exp (b, c); + MPFR_LOG_MSG (("UBF: exp_b=%" MPFR_EXP_FSPEC "d%s " + "diff_exp=%" MPFR_EXP_FSPEC "d%s\n", + (mpfr_eexp_t) exp_b, + exp_b == MPFR_EXP_MAX ? "=MPFR_EXP_MAX" : "", + (mpfr_eexp_t) diff_exp, + diff_exp == MPFR_EXP_MAX ? "=MPFR_EXP_MAX" : "")); + /* If diff_exp == MPFR_EXP_MAX, the actual value can be larger, + but anyway, since mpfr_exp_t >= mp_size_t, this will be the + case c small below, and the exact value does not matter. */ } else { @@ -671,18 +679,17 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode) rnd_mode = MPFR_RNDZ; return mpfr_underflow (a, rnd_mode, MPFR_SIGN(a)); } - /* We cannot have overflow here, except for UBFs. Indeed: + /* We cannot have an overflow here, except for UBFs. Indeed: exp_a = exp_b - cancel + add_exp <= emax - 1 + 1 <= emax. For UBFs, we can have exp_b > emax. */ if (exp_a > __gmpfr_emax) { - MPFR_ASSERTD(exp_b > __gmpfr_emax); + MPFR_ASSERTD (exp_b > __gmpfr_emax); /* since exp_b >= exp_a */ return mpfr_overflow (a, rnd_mode, MPFR_SIGN (a)); } } else /* cancel = 0: MPFR_EXP(a) <- MPFR_EXP(b) + add_exp */ { - /* in case cancel = 0, add_exp can still be 1, in case b is just below a power of two, c is very small, prec(a) < prec(b), and rnd=away or nearest */ |