contrib/gdtoa/strtordd.c

   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  void
  35 #ifdef KR_headers
  36 ULtodd(L, bits, exp, k) ULong *L; ULong *bits; Long exp; int k;
  37 #else
  38 ULtodd(ULong *L, ULong *bits, Long exp, int k)
  39 #endif
  40 {
  41         int i, j;
  42
  43         switch(k & STRTOG_Retmask) {
  44           case STRTOG_NoNumber:
  45           case STRTOG_Zero:
  46                 L[0] = L[1] = L[2] = L[3] = 0;
  47                 break;
  48
  49           case STRTOG_Normal:
  50                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
  51                 L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
  52                           | exp + 0x3ff + 105 << 20;
  53                 exp += 0x3ff + 52;
  54                 if (bits[1] &= 0x1fffff) {
  55                         i = hi0bits(bits[1]) - 11;
  56                         if (i >= exp) {
  57                                 i = exp - 1;
  58                                 exp = 0;
  59                                 }
  60                         else
  61                                 exp -= i;
  62                         if (i > 0) {
  63                                 bits[1] = bits[1] << i | bits[0] >> 32-i;
  64                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  65                                 }
  66                         }
  67                 else if (bits[0]) {
  68                         i = hi0bits(bits[0]) + 21;
  69                         if (i >= exp) {
  70                                 i = exp - 1;
  71                                 exp = 0;
  72                                 }
  73                         else
  74                                 exp -= i;
  75                         if (i < 32) {
  76                                 bits[1] = bits[0] >> 32 - i;
  77                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  78                                 }
  79                         else {
  80                                 bits[1] = bits[0] << i - 32;
  81                                 bits[0] = 0;
  82                                 }
  83                         }
  84                 else {
  85                         L[2] = L[3] = 0;
  86                         break;
  87                         }
  88                 L[2+_1] = bits[0];
  89                 L[2+_0] = bits[1] & 0xfffff | exp << 20;
  90                 break;
  91
  92           case STRTOG_Denormal:
  93                 if (bits[3])
  94                         goto nearly_normal;
  95                 if (bits[2])
  96                         goto partly_normal;
  97                 if (bits[1] & 0xffe00000)
  98                         goto hardly_normal;
  99                 /* completely denormal */
 100                 L[2] = L[3] = 0;
 101                 L[_1] = bits[0];
 102                 L[_0] = bits[1];
 103                 break;
 104
 105           nearly_normal:
 106                 i = hi0bits(bits[3]) - 11;      /* i >= 12 */
 107                 j = 32 - i;
 108                 L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
 109                         | 65 - i << 20;
 110                 L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 111                 L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
 112                 L[2+_1] = bits[0];
 113                 break;
 114
 115           partly_normal:
 116                 i = hi0bits(bits[2]) - 11;
 117                 if (i < 0) {
 118                         j = -i;
 119                         i += 32;
 120                         L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
 121                         L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 122                         L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
 123                         L[2+_1] = bits[0];
 124                         break;
 125                         }
 126                 if (i == 0) {
 127                         L[_0] = bits[2] & 0xfffff | 33 << 20;
 128                         L[_1] = bits[1];
 129                         L[2+_0] = 0;
 130                         L[2+_1] = bits[0];
 131                         break;
 132                         }
 133                 j = 32 - i;
 134                 L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
 135                                 | j + 1 << 20;
 136                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 137                 L[2+_0] = 0;
 138                 L[2+_1] = bits[0] & (1L << j) - 1;
 139                 break;
 140
 141           hardly_normal:
 142                 j = 11 - hi0bits(bits[1]);
 143                 i = 32 - j;
 144                 L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
 145                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 146                 L[2+_0] = 0;
 147                 L[2+_1] = bits[0] & ((ULong)1L << j) - 1;
 148                 break;
 149
 150           case STRTOG_Infinite:
 151                 L[_0] = L[2+_0] = 0x7ff00000;
 152                 L[_1] = L[2+_1] = 0;
 153                 break;
 154
 155           case STRTOG_NaN:
 156                 L[0] = L[2] = d_QNAN0;
 157                 L[1] = L[3] = d_QNAN1;
 158                 break;
 159
 160           case STRTOG_NaNbits:
 161                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
 162                 L[_0] = bits[2] >> 21 | bits[3] << 11
 163                           | (ULong)0x7ff00000L;
 164                 L[2+_1] = bits[0];
 165                 L[2+_0] = bits[1] | (ULong)0x7ff00000L;
 166           }
 167         if (k & STRTOG_Neg) {
 168                 L[_0] |= 0x80000000L;
 169                 L[2+_0] |= 0x80000000L;
 170                 }
 171         }
 172
 173  int
 174 #ifdef KR_headers
 175 strtordd(s, sp, rounding, dd) CONST char *s; char **sp; int rounding; double *dd;
 176 #else
 177 strtordd(CONST char *s, char **sp, int rounding, double *dd)
 178 #endif
 179 {
 180 #ifdef Sudden_Underflow
 181         static FPI fpi0 = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
 182 #else
 183         static FPI fpi0 = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
 184 #endif
 185         FPI *fpi, fpi1;
 186         ULong bits[4];
 187         Long exp;
 188         int k;
 189
 190         fpi = &fpi0;
 191         if (rounding != FPI_Round_near) {
 192                 fpi1 = fpi0;
 193                 fpi1.rounding = rounding;
 194                 fpi = &fpi1;
 195                 }
 196         k = strtodg(s, sp, fpi, &exp, bits);
 197         ULtodd((ULong*)dd, bits, exp, k);
 198         return k;
 199         }