t-get_d_2exp.c
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上传日期:2022-08-06
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- /* Test mpz_get_d_2exp.
- Copyright 2002, 2003 Free Software Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP 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 MP 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 MP Library. If not, see http://www.gnu.org/licenses/. */
- #include <stdio.h>
- #include <stdlib.h>
- #include "gmp.h"
- #include "gmp-impl.h"
- #include "tests.h"
- static void
- check_onebit (void)
- {
- static const unsigned long data[] = {
- 1, 32, 52, 53, 54, 63, 64, 65, 128, 256, 511, 512, 513
- };
- mpz_t z;
- double got, want;
- long got_exp, want_exp;
- int i;
- mpz_init (z);
- for (i = 0; i < numberof (data); i++)
- {
- mpz_set_ui (z, 1L);
- mpz_mul_2exp (z, z, data[i]);
- want = 0.5;
- want_exp = data[i] + 1;
- got = mpz_get_d_2exp (&got_exp, z);
- if (got != want || got_exp != want_exp)
- {
- printf ("mpz_get_d_2exp wrong on 2**%ldn", data[i]);
- mpz_trace (" z ", z);
- d_trace (" want ", want);
- d_trace (" got ", got);
- printf (" want exp %ldn", want_exp);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- mpz_set_si (z, -1L);
- mpz_mul_2exp (z, z, data[i]);
- want = -0.5;
- want_exp = data[i] + 1;
- got = mpz_get_d_2exp (&got_exp, z);
- if (got != want || got_exp != want_exp)
- {
- printf ("mpz_get_d_2exp wrong on -2**%ldn", data[i]);
- mpz_trace (" z ", z);
- d_trace (" want ", want);
- d_trace (" got ", got);
- printf (" want exp %ldn", want_exp);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- }
- mpz_clear (z);
- }
- /* Check that hardware rounding doesn't make mpz_get_d_2exp return a value
- outside its defined range. */
- static void
- check_round (void)
- {
- static const unsigned long data[] = { 1, 32, 53, 54, 64, 128, 256, 512 };
- mpz_t z;
- double got;
- long got_exp;
- int i, rnd_mode, old_rnd_mode;
- mpz_init (z);
- old_rnd_mode = tests_hardware_getround ();
- for (rnd_mode = 0; rnd_mode < 4; rnd_mode++)
- {
- tests_hardware_setround (rnd_mode);
- for (i = 0; i < numberof (data); i++)
- {
- mpz_set_ui (z, 1L);
- mpz_mul_2exp (z, z, data[i]);
- mpz_sub_ui (z, z, 1L);
- got = mpz_get_d_2exp (&got_exp, z);
- if (got < 0.5 || got >= 1.0)
- {
- printf ("mpz_get_d_2exp wrong on 2**%lu-1n", data[i]);
- printf ("result out of range, expect 0.5 <= got < 1.0n");
- printf (" rnd_mode = %dn", rnd_mode);
- printf (" data[i] = %lun", data[i]);
- mpz_trace (" z ", z);
- d_trace (" got ", got);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- mpz_neg (z, z);
- got = mpz_get_d_2exp (&got_exp, z);
- if (got <= -1.0 || got > -0.5)
- {
- printf ("mpz_get_d_2exp wrong on -2**%lu-1n", data[i]);
- printf ("result out of range, expect -1.0 < got <= -0.5n");
- printf (" rnd_mode = %dn", rnd_mode);
- printf (" data[i] = %lun", data[i]);
- mpz_trace (" z ", z);
- d_trace (" got ", got);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- }
- }
- mpz_clear (z);
- tests_hardware_setround (old_rnd_mode);
- }
- static void
- check_rand (void)
- {
- gmp_randstate_ptr rands = RANDS;
- int i;
- mpz_t z;
- double got;
- long got_exp;
- unsigned long bits;
- mpz_init (z);
- for (i = 0; i < 200; i++)
- {
- bits = gmp_urandomm_ui (rands, 512L);
- mpz_urandomb (z, rands, bits);
- got = mpz_get_d_2exp (&got_exp, z);
- if (mpz_sgn (z) == 0)
- continue;
- bits = mpz_sizeinbase (z, 2);
- if (got < 0.5 || got >= 1.0)
- {
- printf ("mpz_get_d_2exp out of range, expect 0.5 <= got < 1.0n");
- mpz_trace (" z ", z);
- d_trace (" got ", got);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- /* FIXME: If mpz_get_d_2exp rounds upwards we might have got_exp ==
- bits+1, so leave this test disabled until we decide if that's what
- should happen, or not. */
- #if 0
- if (got_exp != bits)
- {
- printf ("mpz_get_d_2exp wrong exponentn", i);
- mpz_trace (" z ", z);
- d_trace (" bits ", bits);
- d_trace (" got ", got);
- printf (" got exp %ldn", got_exp);
- abort();
- }
- #endif
- }
- mpz_clear (z);
- }
- int
- main (void)
- {
- tests_start ();
- mp_trace_base = -16;
- check_onebit ();
- check_round ();
- check_rand ();
- tests_end ();
- exit (0);
- }