1 /* Test of modf*() function family. 2 Copyright (C) 2012-2014 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17 static void test_function(void)18test_function (void) 19 { 20 int i; 21 const DOUBLE TWO_MANT_DIG = 22 /* Assume MANT_DIG <= 5 * 31. 23 Use the identity 24 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */ 25 (DOUBLE) (1U << ((MANT_DIG - 1) / 5)) 26 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5)) 27 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5)) 28 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5)) 29 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5)); 30 31 /* Randomized tests. */ 32 for (i = 0; i < SIZEOF (RANDOM); i++) 33 { 34 DOUBLE x = RANDOM[i]; /* 0.0 <= x < 1.0 */ 35 DOUBLE y; 36 DOUBLE z; 37 38 y = MODF (x, &z); 39 ASSERT (z == L_(0.0)); 40 ASSERT (y == x); 41 42 y = MODF (- x, &z); 43 ASSERT (z == L_(0.0)); 44 ASSERT (y == - x); 45 46 y = MODF (L_(1.0) + x, &z); 47 ASSERT (z == L_(1.0)); 48 y -= x; 49 ASSERT (y >= - L_(1.0) / TWO_MANT_DIG); 50 ASSERT (y <= L_(1.0) / TWO_MANT_DIG); 51 52 y = MODF (- L_(1.0) - x, &z); 53 ASSERT (z == - L_(1.0)); 54 y -= - x; 55 ASSERT (y >= - L_(1.0) / TWO_MANT_DIG); 56 ASSERT (y <= L_(1.0) / TWO_MANT_DIG); 57 } 58 } 59 60 volatile DOUBLE x; 61 DOUBLE y; 62 DOUBLE z; 63