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 David M. Gay (dmg at acm dot org, 30 * with " at " changed at "@" and " dot " changed to "."). */ 31 32 #include "gdtoaimp.h" 33 34 static double 35 #ifdef KR_headers 36 ulpdown(d) double *d; 37 #else 38 ulpdown(double *d) 39 #endif 40 { 41 double u; 42 ULong *L = (ULong*)d; 43 44 u = ulp(*d); 45 if (!(L[_1] | L[_0] & 0xfffff) 46 && (L[_0] & 0x7ff00000) > 0x00100000) 47 u *= 0.5; 48 return u; 49 } 50 51 int 52 #ifdef KR_headers 53 strtodI(s, sp, dd) CONST char *s; char **sp; double *dd; 54 #else 55 strtodI(CONST char *s, char **sp, double *dd) 56 #endif 57 { 58 static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI }; 59 ULong bits[2], sign; 60 Long exp; 61 int j, k; 62 typedef union { 63 double d[2]; 64 ULong L[4]; 65 } U; 66 U *u; 67 68 k = strtodg(s, sp, &fpi, &exp, bits); 69 u = (U*)dd; 70 sign = k & STRTOG_Neg ? 0x80000000L : 0; 71 switch(k & STRTOG_Retmask) { 72 case STRTOG_NoNumber: 73 u->d[0] = u->d[1] = 0.; 74 break; 75 76 case STRTOG_Zero: 77 u->d[0] = u->d[1] = 0.; 78 #ifdef Sudden_Underflow 79 if (k & STRTOG_Inexact) { 80 if (sign) 81 u->L[_0] = 0x80100000L; 82 else 83 u->L[2+_0] = 0x100000L; 84 } 85 break; 86 #else 87 goto contain; 88 #endif 89 90 case STRTOG_Denormal: 91 u->L[_1] = bits[0]; 92 u->L[_0] = bits[1]; 93 goto contain; 94 95 case STRTOG_Normal: 96 u->L[_1] = bits[0]; 97 u->L[_0] = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20); 98 contain: 99 j = k & STRTOG_Inexact; 100 if (sign) { 101 u->L[_0] |= sign; 102 j = STRTOG_Inexact - j; 103 } 104 switch(j) { 105 case STRTOG_Inexlo: 106 #ifdef Sudden_Underflow 107 if ((u->L[_0] & 0x7ff00000) < 0x3500000) { 108 u->L[2+_0] = u->L[_0] + 0x3500000; 109 u->L[2+_1] = u->L[_1]; 110 u->d[1] += ulp(u->d[1]); 111 u->L[2+_0] -= 0x3500000; 112 if (!(u->L[2+_0] & 0x7ff00000)) { 113 u->L[2+_0] = sign; 114 u->L[2+_1] = 0; 115 } 116 } 117 else 118 #endif 119 u->d[1] = u->d[0] + ulp(u->d[0]); 120 break; 121 case STRTOG_Inexhi: 122 u->d[1] = u->d[0]; 123 #ifdef Sudden_Underflow 124 if ((u->L[_0] & 0x7ff00000) < 0x3500000) { 125 u->L[_0] += 0x3500000; 126 u->d[0] -= ulpdown(u->d); 127 u->L[_0] -= 0x3500000; 128 if (!(u->L[_0] & 0x7ff00000)) { 129 u->L[_0] = sign; 130 u->L[_1] = 0; 131 } 132 } 133 else 134 #endif 135 u->d[0] -= ulpdown(u->d); 136 break; 137 default: 138 u->d[1] = u->d[0]; 139 } 140 break; 141 142 case STRTOG_Infinite: 143 u->L[_0] = u->L[2+_0] = sign | 0x7ff00000; 144 u->L[_1] = u->L[2+_1] = 0; 145 if (k & STRTOG_Inexact) { 146 if (sign) { 147 u->L[2+_0] = 0xffefffffL; 148 u->L[2+_1] = 0xffffffffL; 149 } 150 else { 151 u->L[_0] = 0x7fefffffL; 152 u->L[_1] = 0xffffffffL; 153 } 154 } 155 break; 156 157 case STRTOG_NaN: 158 u->L[0] = u->L[2] = d_QNAN0; 159 u->L[1] = u->L[3] = d_QNAN1; 160 break; 161 162 case STRTOG_NaNbits: 163 u->L[_0] = u->L[2+_0] = 0x7ff00000 | sign | bits[1]; 164 u->L[_1] = u->L[2+_1] = bits[0]; 165 } 166 return k; 167 } 168