1 /**************************************************************** 2 3 The author of this software is David M. Gay. 4 5 Copyright (C) 1998 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 dmg@acm.org 32 */ 33 34 #include "gdtoaimp.h" 35 36 #ifdef USE_LOCALE 37 #include "locale.h" 38 #endif 39 40 int 41 #ifdef KR_headers 42 gethex(sp, fpi, exp, bp, sign) 43 CONST char **sp; FPI *fpi; Long *exp; Bigint **bp; int sign; 44 #else 45 gethex( CONST char **sp, FPI *fpi, Long *exp, Bigint **bp, int sign) 46 #endif 47 { 48 Bigint *b; 49 CONST unsigned char *decpt, *s0, *s, *s1; 50 int esign, havedig, irv, k, n, nbits, up; 51 ULong L, lostbits, *x; 52 Long e, e1; 53 #ifdef USE_LOCALE 54 unsigned char decimalpoint = *localeconv()->decimal_point; 55 #else 56 #define decimalpoint '.' 57 #endif 58 59 if (!hexdig['0']) 60 hexdig_init_D2A(); 61 havedig = 0; 62 s0 = *(CONST unsigned char **)sp + 2; 63 while(s0[havedig] == '0') 64 havedig++; 65 s0 += havedig; 66 s = s0; 67 decpt = 0; 68 if (!hexdig[*s]) { 69 if (*s == decimalpoint) { 70 decpt = ++s; 71 if (!hexdig[*s]) 72 goto ret0; 73 } 74 else { 75 ret0: 76 *sp = (char*)s; 77 return havedig ? STRTOG_Zero : STRTOG_NoNumber; 78 } 79 while(*s == '0') 80 s++; 81 havedig = 1; 82 if (!hexdig[*s]) 83 goto ret0; 84 s0 = s; 85 } 86 while(hexdig[*s]) 87 s++; 88 if (*s == decimalpoint && !decpt) { 89 decpt = ++s; 90 while(hexdig[*s]) 91 s++; 92 } 93 e = 0; 94 if (decpt) 95 e = -(((Long)(s-decpt)) << 2); 96 s1 = s; 97 switch(*s) { 98 case 'p': 99 case 'P': 100 esign = 0; 101 switch(*++s) { 102 case '-': 103 esign = 1; 104 /* no break */ 105 case '+': 106 s++; 107 } 108 if ((n = hexdig[*s]) == 0 || n > 0x19) { 109 s = s1; 110 break; 111 } 112 e1 = n - 0x10; 113 while((n = hexdig[*++s]) !=0 && n <= 0x19) 114 e1 = 10*e1 + n - 0x10; 115 if (esign) 116 e1 = -e1; 117 e += e1; 118 } 119 *sp = (char*)s; 120 n = s1 - s0 - 1; 121 for(k = 0; n > 7; n >>= 1) 122 k++; 123 b = Balloc(k); 124 x = b->x; 125 n = 0; 126 L = 0; 127 while(s1 > s0) { 128 if (*--s1 == decimalpoint) 129 continue; 130 if (n == 32) { 131 *x++ = L; 132 L = 0; 133 n = 0; 134 } 135 L |= (hexdig[*s1] & 0x0f) << n; 136 n += 4; 137 } 138 *x++ = L; 139 b->wds = n = x - b->x; 140 n = 32*n - hi0bits(L); 141 nbits = fpi->nbits; 142 lostbits = 0; 143 x = b->x; 144 if (n > nbits) { 145 n -= nbits; 146 if (any_on(b,n)) { 147 lostbits = 1; 148 k = n - 1; 149 if (x[k>>kshift] & 1 << (k & kmask)) { 150 lostbits = 2; 151 if (k > 1 && any_on(b,k-1)) 152 lostbits = 3; 153 } 154 } 155 rshift(b, n); 156 e += n; 157 } 158 else if (n < nbits) { 159 n = nbits - n; 160 b = lshift(b, n); 161 e -= n; 162 x = b->x; 163 } 164 if (e > fpi->emax) { 165 ovfl: 166 Bfree(b); 167 *bp = 0; 168 return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi; 169 } 170 irv = STRTOG_Normal; 171 if (e < fpi->emin) { 172 irv = STRTOG_Denormal; 173 n = fpi->emin - e; 174 if (n >= nbits) { 175 switch (fpi->rounding) { 176 case FPI_Round_near: 177 if (n == nbits && (n < 2 || any_on(b,n-1))) 178 goto one_bit; 179 break; 180 case FPI_Round_up: 181 if (!sign) 182 goto one_bit; 183 break; 184 case FPI_Round_down: 185 if (sign) { 186 one_bit: 187 *exp = fpi->emin; 188 x[0] = b->wds = 1; 189 *bp = b; 190 return STRTOG_Denormal | STRTOG_Inexhi 191 | STRTOG_Underflow; 192 } 193 } 194 Bfree(b); 195 *bp = 0; 196 return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow; 197 } 198 k = n - 1; 199 if (lostbits) 200 lostbits = 1; 201 else if (k > 0) 202 lostbits = any_on(b,k); 203 if (x[k>>kshift] & 1 << (k & kmask)) 204 lostbits |= 2; 205 nbits -= n; 206 rshift(b,n); 207 e = fpi->emin; 208 } 209 if (lostbits) { 210 up = 0; 211 switch(fpi->rounding) { 212 case FPI_Round_zero: 213 break; 214 case FPI_Round_near: 215 if (lostbits & 2 216 && (lostbits & 1) | x[0] & 1) 217 up = 1; 218 break; 219 case FPI_Round_up: 220 up = 1 - sign; 221 break; 222 case FPI_Round_down: 223 up = sign; 224 } 225 if (up) { 226 k = b->wds; 227 b = increment(b); 228 x = b->x; 229 if (irv == STRTOG_Denormal) { 230 if (nbits == fpi->nbits - 1 231 && x[nbits >> kshift] & 1 << (nbits & kmask)) 232 irv = STRTOG_Normal; 233 } 234 else if (b->wds > k 235 || (n = nbits & kmask) !=0 236 && hi0bits(x[k-1]) < 32-n) { 237 rshift(b,1); 238 if (++e > fpi->emax) 239 goto ovfl; 240 } 241 irv |= STRTOG_Inexhi; 242 } 243 else 244 irv |= STRTOG_Inexlo; 245 } 246 *bp = b; 247 *exp = e; 248 return irv; 249 } 250