lib/libc/gdtoa/strtordd.c

   1 /* $NetBSD: strtordd.c,v 1.3 2011/03/20 23:15:35 christos Exp $ */
   2
   3 /****************************************************************
   4
   5 The author of this software is David M. Gay.
   6
   7 Copyright (C) 1998, 2000 by Lucent Technologies
   8 All Rights Reserved
   9
  10 Permission to use, copy, modify, and distribute this software and
  11 its documentation for any purpose and without fee is hereby
  12 granted, provided that the above copyright notice appear in all
  13 copies and that both that the copyright notice and this
  14 permission notice and warranty disclaimer appear in supporting
  15 documentation, and that the name of Lucent or any of its entities
  16 not be used in advertising or publicity pertaining to
  17 distribution of the software without specific, written prior
  18 permission.
  19
  20 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  21 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
  22 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
  23 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  24 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
  25 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  26 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
  27 THIS SOFTWARE.
  28
  29 ****************************************************************/
  30
  31 /* Please send bug reports to David M. Gay (dmg at acm dot org,
  32  * with " at " changed at "@" and " dot " changed to ".").      */
  33
  34 #include "gdtoaimp.h"
  35
  36  void
  37 #ifdef KR_headers
  38 ULtodd(L, bits, expt, k) ULong *L; ULong *bits; Long expt; int k;
  39 #else
  40 ULtodd(ULong *L, ULong *bits, Long expt, int k)
  41 #endif
  42 {
  43         int i, j;
  44
  45         switch(k & STRTOG_Retmask) {
  46           case STRTOG_NoNumber:
  47           case STRTOG_Zero:
  48                 L[0] = L[1] = L[2] = L[3] = 0;
  49                 break;
  50
  51           case STRTOG_Normal:
  52                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
  53                 L[_0] = (bits[2] >> 21) | (bits[3] << 11 & 0xfffff)
  54                           | ((expt + 0x3ff + 105) << 20);
  55                 expt += 0x3ff + 52;
  56                 if (bits[1] &= 0x1fffff) {
  57                         i = hi0bits(bits[1]) - 11;
  58                         if (i >= expt) {
  59                                 i = expt - 1;
  60                                 expt = 0;
  61                                 }
  62                         else
  63                                 expt -= i;
  64                         if (i > 0) {
  65                                 bits[1] = bits[1] << i | bits[0] >> (32-i);
  66                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  67                                 }
  68                         }
  69                 else if (bits[0]) {
  70                         i = hi0bits(bits[0]) + 21;
  71                         if (i >= expt) {
  72                                 i = expt - 1;
  73                                 expt = 0;
  74                                 }
  75                         else
  76                                 expt -= i;
  77                         if (i < 32) {
  78                                 bits[1] = bits[0] >> (32 - i);
  79                                 bits[0] = bits[0] << i & (ULong)0xffffffffL;
  80                                 }
  81                         else {
  82                                 bits[1] = bits[0] << (i - 32);
  83                                 bits[0] = 0;
  84                                 }
  85                         }
  86                 else {
  87                         L[2] = L[3] = 0;
  88                         break;
  89                         }
  90                 L[2+_1] = bits[0];
  91                 L[2+_0] = (bits[1] & 0xfffff) | (expt << 20);
  92                 break;
  93
  94           case STRTOG_Denormal:
  95                 if (bits[3])
  96                         goto nearly_normal;
  97                 if (bits[2])
  98                         goto partly_normal;
  99                 if (bits[1] & 0xffe00000)
 100                         goto hardly_normal;
 101                 /* completely denormal */
 102                 L[2] = L[3] = 0;
 103                 L[_1] = bits[0];
 104                 L[_0] = bits[1];
 105                 break;
 106
 107           nearly_normal:
 108                 i = hi0bits(bits[3]) - 11;      /* i >= 12 */
 109                 j = 32 - i;
 110                 L[_0] = ((bits[3] << i | bits[2] >> j) & 0xfffff)
 111                         | ((65 - i) << 20);
 112                 L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 113                 L[2+_0] = bits[1] & (((ULong)1L << j) - 1);
 114                 L[2+_1] = bits[0];
 115                 break;
 116
 117           partly_normal:
 118                 i = hi0bits(bits[2]) - 11;
 119                 if (i < 0) {
 120                         j = -i;
 121                         i += 32;
 122                         L[_0] = (bits[2] >> j & 0xfffff) | ((33 + j) << 20);
 123                         L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 124                         L[2+_0] = bits[1] & (((ULong)1L << j) - 1);
 125                         L[2+_1] = bits[0];
 126                         break;
 127                         }
 128                 if (i == 0) {
 129                         L[_0] = (bits[2] & 0xfffff) | (33 << 20);
 130                         L[_1] = bits[1];
 131                         L[2+_0] = 0;
 132                         L[2+_1] = bits[0];
 133                         break;
 134                         }
 135                 j = 32 - i;
 136                 L[_0] = (((bits[2] << i) | (bits[1] >> j)) & 0xfffff)
 137                                 | ((j + 1) << 20);
 138                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 139                 L[2+_0] = 0;
 140                 L[2+_1] = bits[0] & ((1L << j) - 1);
 141                 break;
 142
 143           hardly_normal:
 144                 j = 11 - hi0bits(bits[1]);
 145                 i = 32 - j;
 146                 L[_0] = (bits[1] >> j & 0xfffff) | ((j + 1) << 20);
 147                 L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 148                 L[2+_0] = 0;
 149                 L[2+_1] = bits[0] & (((ULong)1L << j) - 1);
 150                 break;
 151
 152           case STRTOG_Infinite:
 153                 L[_0] = L[2+_0] = 0x7ff00000;
 154                 L[_1] = L[2+_1] = 0;
 155                 break;
 156
 157           case STRTOG_NaN:
 158                 L[0] = L[2] = d_QNAN0;
 159                 L[1] = L[3] = d_QNAN1;
 160                 break;
 161
 162           case STRTOG_NaNbits:
 163                 L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
 164                 L[_0] = bits[2] >> 21 | bits[3] << 11
 165                           | (ULong)0x7ff00000L;
 166                 L[2+_1] = bits[0];
 167                 L[2+_0] = bits[1] | (ULong)0x7ff00000L;
 168           }
 169         if (k & STRTOG_Neg) {
 170                 L[_0] |= 0x80000000L;
 171                 L[2+_0] |= 0x80000000L;
 172                 }
 173         }
 174
 175  int
 176 #ifdef KR_headers
 177 strtordd(s, sp, rounding, dd) CONST char *s; char **sp; int rounding; double *dd;
 178 #else
 179 strtordd(CONST char *s, char **sp, int rounding, double *dd)
 180 #endif
 181 {
 182 #ifdef Sudden_Underflow
 183         static CONST FPI fpi0 = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
 184 #else
 185         static CONST FPI fpi0 = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
 186 #endif
 187         CONST FPI *fpi;
 188         FPI fpi1;
 189         ULong bits[4];
 190         Long expt;
 191         int k;
 192
 193         fpi = &fpi0;
 194         if (rounding != FPI_Round_near) {
 195                 fpi1 = fpi0;
 196                 fpi1.rounding = rounding;
 197                 fpi = &fpi1;
 198                 }
 199         k = strtodg(s, sp, fpi, &expt, bits);
 200         if (k == STRTOG_NoMemory)
 201                 return k;
 202         ULtodd((ULong*)dd, bits, expt, k);
 203         return k;
 204         }