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
  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  void
  41 #ifdef KR_headers
  42 ULtodd(L, bits, exp, k) ULong *L; ULong *bits; Long exp; int k;
  43 #else
  44 ULtodd(ULong *L, ULong *bits, Long exp, int k)
  45 #endif
  46 {
  47         int i, j;
  48
  49         switch(k & STRTOG_Retmask) {
  50           case STRTOG_NoNumber:
  51           case STRTOG_Zero:
  52                 L[0] = L[1] = L[2] = L[3] = 0;
  53                 break;
  54
  55           case STRTOG_Normal:
  56                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
  57                 L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
  58                           | exp + 0x3ff + 105 << 20;
  59                 exp += 0x3ff + 52;
  60                 if (bits[1] &= 0x1fffff) {
  61                         i = hi0bits(bits[1]) - 11;
  62                         if (i >= exp) {
  63                                 i = exp - 1;
  64                                 exp = 0;
  65                                 }
  66                         else
  67                                 exp -= i;
  68                         if (i > 0) {
  69                                 bits[1] = bits[1] << i | bits[0] >> 32-i;
  70                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  71                                 }
  72                         }
  73                 else if (bits[0]) {
  74                         i = hi0bits(bits[0]) + 21;
  75                         if (i >= exp) {
  76                                 i = exp - 1;
  77                                 exp = 0;
  78                                 }
  79                         else
  80                                 exp -= i;
  81                         if (i < 32) {
  82                                 bits[1] = bits[0] >> 32 - i;
  83                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  84                                 }
  85                         else {
  86                                 bits[1] = bits[0] << i - 32;
  87                                 bits[0] = 0;
  88                                 }
  89                         }
  90                 else {
  91                         L[2] = L[3] = 0;
  92                         break;
  93                         }
  94                 L[2+_1] = bits[0];
  95                 L[2+_0] = bits[1] & 0xfffff | exp << 20;
  96                 break;
  97
  98           case STRTOG_Denormal:
  99                 if (bits[3])
 100                         goto nearly_normal;
 101                 if (bits[2])
 102                         goto partly_normal;
 103                 if (bits[1] & 0xffe00000)
 104                         goto hardly_normal;
 105                 /* completely denormal */
 106                 L[2] = L[3] = 0;
 107                 L[_1] = bits[0];
 108                 L[_0] = bits[1];
 109                 break;
 110
 111           nearly_normal:
 112                 i = hi0bits(bits[3]) - 11;      /* i >= 12 */
 113                 j = 32 - i;
 114                 L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
 115                         | 65 - i << 20;
 116                 L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 117                 L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
 118                 L[2+_1] = bits[0];
 119                 break;
 120
 121           partly_normal:
 122                 i = hi0bits(bits[2]) - 11;
 123                 if (i < 0) {
 124                         j = -i;
 125                         i += 32;
 126                         L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
 127                         L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 128                         L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
 129                         L[2+_1] = bits[0];
 130                         break;
 131                         }
 132                 if (i == 0) {
 133                         L[_0] = bits[2] & 0xfffff | 33 << 20;
 134                         L[_1] = bits[1];
 135                         L[2+_0] = 0;
 136                         L[2+_1] = bits[0];
 137                         break;
 138                         }
 139                 j = 32 - i;
 140                 L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
 141                                 | j + 1 << 20;
 142                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 143                 L[2+_0] = 0;
 144                 L[2+_1] = bits[0] & (1L << j) - 1;
 145                 break;
 146
 147           hardly_normal:
 148                 j = 11 - hi0bits(bits[1]);
 149                 i = 32 - j;
 150                 L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
 151                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 152                 L[2+_0] = 0;
 153                 L[2+_1] = bits[0] & ((ULong)1L << j) - 1;
 154                 break;
 155
 156           case STRTOG_Infinite:
 157                 L[_0] = L[2+_0] = 0x7ff00000;
 158                 L[_1] = L[2+_1] = 0;
 159                 break;
 160
 161           case STRTOG_NaN:
 162                 L[_0] = L[2+_0] = 0x7fffffff;
 163                 L[_1] = L[2+_1] = (ULong)-1;
 164                 break;
 165
 166           case STRTOG_NaNbits:
 167                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
 168                 L[_0] = bits[2] >> 21 | bits[3] << 11
 169                           | (ULong)0x7ff00000L;
 170                 L[2+_1] = bits[0];
 171                 L[2+_0] = bits[1] | (ULong)0x7ff00000L;
 172           }
 173         if (k & STRTOG_Neg) {
 174                 L[_0] |= 0x80000000L;
 175                 L[2+_0] |= 0x80000000L;
 176                 }
 177         }
 178
 179  int
 180 #ifdef KR_headers
 181 strtordd(s, sp, rounding, dd) CONST char *s; char **sp; int rounding; double *dd;
 182 #else
 183 strtordd(CONST char *s, char **sp, int rounding, double *dd)
 184 #endif
 185 {
 186 #ifdef Sudden_Underflow
 187         static FPI fpi0 = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
 188 #else
 189         static FPI fpi0 = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
 190 #endif
 191         FPI *fpi, fpi1;
 192         ULong bits[4];
 193         Long exp;
 194         int k;
 195
 196         fpi = &fpi0;
 197         if (rounding != FPI_Round_near) {
 198                 fpi1 = fpi0;
 199                 fpi1.rounding = rounding;
 200                 fpi = &fpi1;
 201                 }
 202         k = strtodg(s, sp, fpi, &exp, bits);
 203         ULtodd((ULong*)dd, bits, exp, k);
 204         return k;
 205         }