/* Test file for mpfr_subnormalize. Copyright 2005-2015 Free Software Foundation, Inc. Contributed by the AriC and Caramel projects, INRIA. This file is part of the GNU MPFR Library. The GNU MPFR Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. The GNU MPFR Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include #include "mpfr-test.h" static const struct { const char *in; int i; mpfr_rnd_t rnd; const char *out; int j; } tab[] = { /* 4th field: use the mpfr_dump format, in case of error. */ {"1E1", 0, MPFR_RNDN, "0.100000000E2", 0}, {"1E1", -1, MPFR_RNDZ, "0.100000000E2", -1}, {"1E1", -1, MPFR_RNDD, "0.100000000E2", -1}, {"1E1", 1, MPFR_RNDU, "0.100000000E2", 1}, {"0.10000E-10", 0, MPFR_RNDN, "0.100000000E-10", 0}, {"0.10001E-10", 0, MPFR_RNDN, "0.100000000E-10", -1}, {"0.11001E-10", 0, MPFR_RNDN, "0.100000000E-9", 1}, {"0.11001E-10", 0, MPFR_RNDZ, "0.100000000E-10", -1}, {"0.11001E-10", 0, MPFR_RNDU, "0.100000000E-9", 1}, {"0.11000E-10", 0, MPFR_RNDN, "0.100000000E-9", 1}, {"0.11000E-10", -1, MPFR_RNDN, "0.100000000E-9", 1}, {"0.11000E-10", 1, MPFR_RNDN, "0.100000000E-10", -1}, {"0.11111E-8", 0, MPFR_RNDN, "0.100000000E-7", 1}, {"0.10111E-8", 0, MPFR_RNDN, "0.110000000E-8", 1}, {"0.11110E-8", -1, MPFR_RNDN, "0.100000000E-7", 1}, {"0.10110E-8", 1, MPFR_RNDN, "0.101000000E-8", -1} }; static void check1 (void) { mpfr_t x; int i, j, k, s, old_inex, tiny, expj; mpfr_exp_t emin, emax; unsigned int expflags, flags; emin = mpfr_get_emin (); emax = mpfr_get_emax (); mpfr_set_default_prec (9); mpfr_set_emin (-10); mpfr_set_emax (10); mpfr_init (x); for (i = 0; i < (sizeof (tab) / sizeof (tab[0])); i++) for (s = 0; s <= (tab[i].rnd == MPFR_RNDN); s++) for (k = 0; k <= 1; k++) { mpfr_set_str (x, tab[i].in, 2, MPFR_RNDN); old_inex = tab[i].i; expj = tab[i].j; if (s) { mpfr_neg (x, x, MPFR_RNDN); old_inex = - old_inex; expj = - expj; } if (k && old_inex) old_inex = old_inex < 0 ? INT_MIN : INT_MAX; tiny = MPFR_GET_EXP (x) <= -3; mpfr_clear_flags (); j = mpfr_subnormalize (x, old_inex, tab[i].rnd); expflags = (tiny ? MPFR_FLAGS_UNDERFLOW : 0) | (expj ? MPFR_FLAGS_INEXACT : 0); flags = __gmpfr_flags; if (s) mpfr_neg (x, x, MPFR_RNDN); if (mpfr_cmp_str (x, tab[i].out, 2, MPFR_RNDN) != 0 || flags != expflags || ! SAME_SIGN (j, expj)) { const char *sgn = s ? "-" : ""; printf ("Error for i = %d (old_inex = %d), k = %d, x = %s%s\n" "Expected: %s%s\nGot: ", i, old_inex, k, sgn, tab[i].in, sgn, tab[i].out); if (s) mpfr_neg (x, x, MPFR_RNDN); mpfr_dump (x); printf ("Expected flags = %u, got %u\n", expflags, flags); printf ("Expected ternary value = %d, got %d\n", expj, j); exit (1); } } mpfr_clear (x); MPFR_ASSERTN (mpfr_get_emin () == -10); MPFR_ASSERTN (mpfr_get_emax () == 10); set_emin (emin); set_emax (emax); } /* bug found by Kevin P. Rauch on 22 Oct 2007 */ static void check2 (void) { mpfr_t x, y, z; int tern; mpfr_exp_t emin; emin = mpfr_get_emin (); mpfr_init2 (x, 32); mpfr_init2 (y, 32); mpfr_init2 (z, 32); mpfr_set_ui (x, 0xC0000000U, MPFR_RNDN); mpfr_neg (x, x, MPFR_RNDN); mpfr_set_ui (y, 0xFFFFFFFEU, MPFR_RNDN); mpfr_set_exp (x, 0); mpfr_set_exp (y, 0); mpfr_set_emin (-29); tern = mpfr_mul (z, x, y, MPFR_RNDN); /* z = -0.BFFFFFFE, tern > 0 */ tern = mpfr_subnormalize (z, tern, MPFR_RNDN); /* z should be -0.75 */ MPFR_ASSERTN (tern < 0 && mpfr_cmp_si_2exp (z, -3, -2) == 0); mpfr_clear (x); mpfr_clear (y); mpfr_clear (z); MPFR_ASSERTN (mpfr_get_emin () == -29); set_emin (emin); } /* bug found by Kevin P. Rauch on 22 Oct 2007 */ static void check3 (void) { mpfr_t x, y, z; int tern; mpfr_exp_t emin; emin = mpfr_get_emin (); mpfr_init2 (x, 32); mpfr_init2 (y, 32); mpfr_init2 (z, 32); mpfr_set_ui (x, 0xBFFFFFFFU, MPFR_RNDN); /* 3221225471/2^32 */ mpfr_set_ui (y, 0x80000001U, MPFR_RNDN); /* 2147483649/2^32 */ mpfr_set_exp (x, 0); mpfr_set_exp (y, 0); mpfr_set_emin (-1); /* the exact product is 6917529028714823679/2^64, which is rounded to 3/8 = 0.375, which is smaller, thus tern < 0 */ tern = mpfr_mul (z, x, y, MPFR_RNDN); MPFR_ASSERTN (tern < 0 && mpfr_cmp_ui_2exp (z, 3, -3) == 0); tern = mpfr_subnormalize (z, tern, MPFR_RNDN); /* since emin = -1, and EXP(z)=-1, z should be rounded to precision EXP(z)-emin+1 = 1, i.e., z should be a multiple of the smallest possible positive representable value with emin=-1, which is 1/4. The two possible values are 1/4 and 2/4, which are at equal distance of z. But since tern < 0, we should choose the largest value, i.e., 2/4. */ MPFR_ASSERTN (tern > 0 && mpfr_cmp_ui_2exp (z, 1, -1) == 0); /* here is another test for the alternate case, where z was rounded up first, thus we have to round down */ mpfr_set_str_binary (x, "0.11111111111010110101011011011011"); mpfr_set_str_binary (y, "0.01100000000001111100000000001110"); tern = mpfr_mul (z, x, y, MPFR_RNDN); MPFR_ASSERTN (tern > 0 && mpfr_cmp_ui_2exp (z, 3, -3) == 0); tern = mpfr_subnormalize (z, tern, MPFR_RNDN); MPFR_ASSERTN (tern < 0 && mpfr_cmp_ui_2exp (z, 1, -2) == 0); /* finally the case where z was exact, which we simulate here */ mpfr_set_ui_2exp (z, 3, -3, MPFR_RNDN); tern = mpfr_subnormalize (z, 0, MPFR_RNDN); MPFR_ASSERTN (tern > 0 && mpfr_cmp_ui_2exp (z, 1, -1) == 0); mpfr_clear (x); mpfr_clear (y); mpfr_clear (z); MPFR_ASSERTN (mpfr_get_emin () == -1); set_emin (emin); } int main (int argc, char *argv[]) { tests_start_mpfr (); check1 (); check2 (); check3 (); tests_end_mpfr (); return 0; }