1/* Test of splitting a 'long double' into fraction and mantissa. 2 Copyright (C) 2007-2010 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/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ 18 19#include <config.h> 20 21#include <math.h> 22 23#include "signature.h" 24SIGNATURE_CHECK (frexpl, long double, (long double, int *)); 25 26#include <float.h> 27 28#include "fpucw.h" 29#include "isnanl-nolibm.h" 30#include "nan.h" 31#include "macros.h" 32 33/* Avoid some warnings from "gcc -Wshadow". 34 This file doesn't use the exp() function. */ 35#undef exp 36#define exp exponent 37 38/* On MIPS IRIX machines, LDBL_MIN_EXP is -1021, but the smallest reliable 39 exponent for 'long double' is -964. Similarly, on PowerPC machines, 40 LDBL_MIN_EXP is -1021, but the smallest reliable exponent for 'long double' 41 is -968. For exponents below that, the precision may be truncated to the 42 precision used for 'double'. */ 43#ifdef __sgi 44# define MIN_NORMAL_EXP (LDBL_MIN_EXP + 57) 45#elif defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__ 46# define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53) 47#else 48# define MIN_NORMAL_EXP LDBL_MIN_EXP 49#endif 50 51/* On HP-UX 10.20, negating 0.0L does not yield -0.0L. 52 So we use minus_zero instead. 53 IRIX cc can't put -0.0L into .data, but can compute at runtime. 54 Note that the expression -LDBL_MIN * LDBL_MIN does not work on other 55 platforms, such as when cross-compiling to PowerPC on MacOS X 10.5. */ 56#if defined __hpux || defined __sgi 57static long double 58compute_minus_zero (void) 59{ 60 return -LDBL_MIN * LDBL_MIN; 61} 62# define minus_zero compute_minus_zero () 63#else 64long double minus_zero = -0.0L; 65#endif 66 67static long double 68my_ldexp (long double x, int d) 69{ 70 for (; d > 0; d--) 71 x *= 2.0L; 72 for (; d < 0; d++) 73 x *= 0.5L; 74 return x; 75} 76 77int 78main () 79{ 80 int i; 81 long double x; 82 DECL_LONG_DOUBLE_ROUNDING 83 84 BEGIN_LONG_DOUBLE_ROUNDING (); 85 86 { /* NaN. */ 87 int exp = -9999; 88 long double mantissa; 89 x = NaNl (); 90 mantissa = frexpl (x, &exp); 91 ASSERT (isnanl (mantissa)); 92 } 93 94 { /* Positive infinity. */ 95 int exp = -9999; 96 long double mantissa; 97 x = 1.0L / 0.0L; 98 mantissa = frexpl (x, &exp); 99 ASSERT (mantissa == x); 100 } 101 102 { /* Negative infinity. */ 103 int exp = -9999; 104 long double mantissa; 105 x = -1.0L / 0.0L; 106 mantissa = frexpl (x, &exp); 107 ASSERT (mantissa == x); 108 } 109 110 { /* Positive zero. */ 111 int exp = -9999; 112 long double mantissa; 113 x = 0.0L; 114 mantissa = frexpl (x, &exp); 115 ASSERT (exp == 0); 116 ASSERT (mantissa == x); 117 ASSERT (!signbit (mantissa)); 118 } 119 120 { /* Negative zero. */ 121 int exp = -9999; 122 long double mantissa; 123 x = minus_zero; 124 mantissa = frexpl (x, &exp); 125 ASSERT (exp == 0); 126 ASSERT (mantissa == x); 127 ASSERT (signbit (mantissa)); 128 } 129 130 for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L) 131 { 132 int exp = -9999; 133 long double mantissa = frexpl (x, &exp); 134 ASSERT (exp == i); 135 ASSERT (mantissa == 0.5L); 136 } 137 for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L) 138 { 139 int exp = -9999; 140 long double mantissa = frexpl (x, &exp); 141 ASSERT (exp == i); 142 ASSERT (mantissa == 0.5L); 143 } 144 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L) 145 { 146 int exp = -9999; 147 long double mantissa = frexpl (x, &exp); 148 ASSERT (exp == i); 149 ASSERT (mantissa == 0.5L); 150 } 151 152 for (i = 1, x = -1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L) 153 { 154 int exp = -9999; 155 long double mantissa = frexpl (x, &exp); 156 ASSERT (exp == i); 157 ASSERT (mantissa == -0.5L); 158 } 159 for (i = 1, x = -1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L) 160 { 161 int exp = -9999; 162 long double mantissa = frexpl (x, &exp); 163 ASSERT (exp == i); 164 ASSERT (mantissa == -0.5L); 165 } 166 for (; i >= LDBL_MIN_EXP - 100 && x < 0.0L; i--, x *= 0.5L) 167 { 168 int exp = -9999; 169 long double mantissa = frexpl (x, &exp); 170 ASSERT (exp == i); 171 ASSERT (mantissa == -0.5L); 172 } 173 174 for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L) 175 { 176 int exp = -9999; 177 long double mantissa = frexpl (x, &exp); 178 ASSERT (exp == i); 179 ASSERT (mantissa == 0.505L); 180 } 181 for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L) 182 { 183 int exp = -9999; 184 long double mantissa = frexpl (x, &exp); 185 ASSERT (exp == i); 186 ASSERT (mantissa == 0.505L); 187 } 188 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L) 189 { 190 int exp = -9999; 191 long double mantissa = frexpl (x, &exp); 192 ASSERT (exp == i); 193 ASSERT (mantissa >= 0.5L); 194 ASSERT (mantissa < 1.0L); 195 ASSERT (mantissa == my_ldexp (x, - exp)); 196 } 197 198 for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L) 199 { 200 int exp = -9999; 201 long double mantissa = frexpl (x, &exp); 202 ASSERT (exp == i); 203 ASSERT (mantissa == 0.866025L); 204 } 205 for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L) 206 { 207 int exp = -9999; 208 long double mantissa = frexpl (x, &exp); 209 ASSERT (exp == i); 210 ASSERT (mantissa == 0.866025L); 211 } 212 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L) 213 { 214 int exp = -9999; 215 long double mantissa = frexpl (x, &exp); 216 ASSERT (exp == i || exp == i + 1); 217 ASSERT (mantissa >= 0.5L); 218 ASSERT (mantissa < 1.0L); 219 ASSERT (mantissa == my_ldexp (x, - exp)); 220 } 221 222 return 0; 223} 224