1 /**************************************************************** 2 3 The author of this software is David M. Gay. 4 5 Copyright (C) 1998, 2000 by Lucent Technologies 6 All Rights Reserved 7 8 Permission to use, copy, modify, and distribute this software and 9 its documentation for any purpose and without fee is hereby 10 granted, provided that the above copyright notice appear in all 11 copies and that both that the copyright notice and this 12 permission notice and warranty disclaimer appear in supporting 13 documentation, and that the name of Lucent or any of its entities 14 not be used in advertising or publicity pertaining to 15 distribution of the software without specific, written prior 16 permission. 17 18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. 20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY 21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER 23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF 25 THIS SOFTWARE. 26 27 ****************************************************************/ 28 29 /* Please send bug reports to 30 David M. Gay 31 Bell Laboratories, Room 2C-463 32 600 Mountain Avenue 33 Murray Hill, NJ 07974-0636 34 U.S.A. 35 dmg@bell-labs.com 36 */ 37 38 #include "gdtoaimp.h" 39 40 static double 41 #ifdef KR_headers 42 ulpdown(d) double *d; 43 #else 44 ulpdown(double *d) 45 #endif 46 { 47 double u; 48 ULong *L = (ULong*)d; 49 50 u = ulp(*d); 51 if (!(L[_1] | L[_0] & 0xfffff) 52 && (L[_0] & 0x7ff00000) > 0x00100000) 53 u *= 0.5; 54 return u; 55 } 56 57 int 58 #ifdef KR_headers 59 strtodI(s, sp, dd) CONST char *s; char **sp; double *dd; 60 #else 61 strtodI(CONST char *s, char **sp, double *dd) 62 #endif 63 { 64 #ifdef Sudden_Underflow 65 static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, 1 }; 66 #else 67 static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, 0 }; 68 #endif 69 ULong bits[2], sign; 70 Long exp; 71 int j, k; 72 typedef union { 73 double d[2]; 74 ULong L[4]; 75 } U; 76 U *u; 77 78 k = strtodg(s, sp, &fpi, &exp, bits); 79 u = (U*)dd; 80 sign = k & STRTOG_Neg ? 0x80000000L : 0; 81 switch(k & STRTOG_Retmask) { 82 case STRTOG_NoNumber: 83 u->d[0] = u->d[1] = 0.; 84 break; 85 86 case STRTOG_Zero: 87 u->d[0] = u->d[1] = 0.; 88 #ifdef Sudden_Underflow 89 if (k & STRTOG_Inexact) { 90 if (sign) 91 u->L[_0] = 0x80100000L; 92 else 93 u->L[2+_0] = 0x100000L; 94 } 95 break; 96 #else 97 goto contain; 98 #endif 99 100 case STRTOG_Denormal: 101 u->L[_1] = bits[0]; 102 u->L[_0] = bits[1]; 103 goto contain; 104 105 case STRTOG_Normal: 106 u->L[_1] = bits[0]; 107 u->L[_0] = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20); 108 contain: 109 j = k & STRTOG_Inexact; 110 if (sign) { 111 u->L[_0] |= sign; 112 j = STRTOG_Inexact - j; 113 } 114 switch(j) { 115 case STRTOG_Inexlo: 116 #ifdef Sudden_Underflow 117 if ((u->L[_0] & 0x7ff00000) < 0x3500000) { 118 u->L[2+_0] = u->L[_0] + 0x3500000; 119 u->L[2+_1] = u->L[_1]; 120 u->d[1] += ulp(u->d[1]); 121 u->L[2+_0] -= 0x3500000; 122 if (!(u->L[2+_0] & 0x7ff00000)) { 123 u->L[2+_0] = sign; 124 u->L[2+_1] = 0; 125 } 126 } 127 else 128 #endif 129 u->d[1] = u->d[0] + ulp(u->d[0]); 130 break; 131 case STRTOG_Inexhi: 132 u->d[1] = u->d[0]; 133 #ifdef Sudden_Underflow 134 if ((u->L[_0] & 0x7ff00000) < 0x3500000) { 135 u->L[_0] += 0x3500000; 136 u->d[0] -= ulpdown(u->d); 137 u->L[_0] -= 0x3500000; 138 if (!(u->L[_0] & 0x7ff00000)) { 139 u->L[_0] = sign; 140 u->L[_1] = 0; 141 } 142 } 143 else 144 #endif 145 u->d[0] -= ulpdown(u->d); 146 break; 147 default: 148 u->d[1] = u->d[0]; 149 } 150 break; 151 152 case STRTOG_Infinite: 153 u->L[_0] = u->L[2+_0] = sign | 0x7ff00000; 154 u->L[_1] = u->L[2+_1] = 0; 155 if (k & STRTOG_Inexact) { 156 if (sign) { 157 u->L[2+_0] = 0xffefffffL; 158 u->L[2+_1] = 0xffffffffL; 159 } 160 else { 161 u->L[_0] = 0x7fefffffL; 162 u->L[_1] = 0xffffffffL; 163 } 164 } 165 break; 166 167 case STRTOG_NaN: 168 u->L[_0] = u->L[2+_0] = 0x7fffffff | sign; 169 u->L[_1] = u->L[2+_1] = (ULong)-1; 170 break; 171 172 case STRTOG_NaNbits: 173 u->L[_0] = u->L[2+_0] = 0x7ff00000 | sign | bits[1]; 174 u->L[_1] = u->L[2+_1] = bits[0]; 175 } 176 return k; 177 } 178