lib/libc/gdtoa/strtopdd.c

   1 /* $NetBSD: strtopdd.c,v 1.1.1.1 2006/01/25 15:18:53 kleink 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  int
  37 #ifdef KR_headers
  38 strtopdd(s, sp, dd) CONST char *s; char **sp; double *dd;
  39 #else
  40 strtopdd(CONST char *s, char **sp, double *dd)
  41 #endif
  42 {
  43 #ifdef Sudden_Underflow
  44         static FPI fpi = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
  45 #else
  46         static FPI fpi = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
  47 #endif
  48         ULong bits[4];
  49         Long exp;
  50         int i, j, rv;
  51         typedef union {
  52                 double d[2];
  53                 ULong L[4];
  54                 } U;
  55         U *u;
  56
  57         rv = strtodg(s, sp, &fpi, &exp, bits);
  58         if (rv == STRTOG_NoMemory)
  59                 return rv;
  60         u = (U*)dd;
  61         switch(rv & STRTOG_Retmask) {
  62           case STRTOG_NoNumber:
  63           case STRTOG_Zero:
  64                 u->d[0] = u->d[1] = 0.;
  65                 break;
  66
  67           case STRTOG_Normal:
  68                 u->L[_1] = (bits[1] >> 21 | bits[2] << 11) & 0xffffffffL;
  69                 u->L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
  70                           | exp + 0x3ff + 105 << 20;
  71                 exp += 0x3ff + 52;
  72                 if (bits[1] &= 0x1fffff) {
  73                         i = hi0bits(bits[1]) - 11;
  74                         if (i >= exp) {
  75                                 i = exp - 1;
  76                                 exp = 0;
  77                                 }
  78                         else
  79                                 exp -= i;
  80                         if (i > 0) {
  81                                 bits[1] = bits[1] << i | bits[0] >> 32-i;
  82                                 bits[0] = bits[0] << i & 0xffffffffL;
  83                                 }
  84                         }
  85                 else if (bits[0]) {
  86                         i = hi0bits(bits[0]) + 21;
  87                         if (i >= exp) {
  88                                 i = exp - 1;
  89                                 exp = 0;
  90                                 }
  91                         else
  92                                 exp -= i;
  93                         if (i < 32) {
  94                                 bits[1] = bits[0] >> 32 - i;
  95                                 bits[0] = bits[0] << i & 0xffffffffL;
  96                                 }
  97                         else {
  98                                 bits[1] = bits[0] << i - 32;
  99                                 bits[0] = 0;
 100                                 }
 101                         }
 102                 else {
 103                         u->L[2] = u->L[3] = 0;
 104                         break;
 105                         }
 106                 u->L[2+_1] = bits[0];
 107                 u->L[2+_0] = bits[1] & 0xfffff | exp << 20;
 108                 break;
 109
 110           case STRTOG_Denormal:
 111                 if (bits[3])
 112                         goto nearly_normal;
 113                 if (bits[2])
 114                         goto partly_normal;
 115                 if (bits[1] & 0xffe00000)
 116                         goto hardly_normal;
 117                 /* completely denormal */
 118                 u->L[2] = u->L[3] = 0;
 119                 u->L[_1] = bits[0];
 120                 u->L[_0] = bits[1];
 121                 break;
 122
 123           nearly_normal:
 124                 i = hi0bits(bits[3]) - 11;      /* i >= 12 */
 125                 j = 32 - i;
 126                 u->L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
 127                         | 65 - i << 20;
 128                 u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 129                 u->L[2+_0] = bits[1] & (1L << j) - 1;
 130                 u->L[2+_1] = bits[0];
 131                 break;
 132
 133           partly_normal:
 134                 i = hi0bits(bits[2]) - 11;
 135                 if (i < 0) {
 136                         j = -i;
 137                         i += 32;
 138                         u->L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
 139                         u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
 140                         u->L[2+_0] = bits[1] & (1L << j) - 1;
 141                         u->L[2+_1] = bits[0];
 142                         break;
 143                         }
 144                 if (i == 0) {
 145                         u->L[_0] = bits[2] & 0xfffff | 33 << 20;
 146                         u->L[_1] = bits[1];
 147                         u->L[2+_0] = 0;
 148                         u->L[2+_1] = bits[0];
 149                         break;
 150                         }
 151                 j = 32 - i;
 152                 u->L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
 153                                 | j + 1 << 20;
 154                 u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 155                 u->L[2+_0] = 0;
 156                 u->L[2+_1] = bits[0] & (1L << j) - 1;
 157                 break;
 158
 159           hardly_normal:
 160                 j = 11 - hi0bits(bits[1]);
 161                 i = 32 - j;
 162                 u->L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
 163                 u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
 164                 u->L[2+_0] = 0;
 165                 u->L[2+_1] = bits[0] & (1L << j) - 1;
 166                 break;
 167
 168           case STRTOG_Infinite:
 169                 u->L[_0] = u->L[2+_0] = 0x7ff00000;
 170                 u->L[_1] = u->L[2+_1] = 0;
 171                 break;
 172
 173           case STRTOG_NaN:
 174                 u->L[0] = u->L[2] = d_QNAN0;
 175                 u->L[1] = u->L[3] = d_QNAN1;
 176           }
 177         if (rv & STRTOG_Neg) {
 178                 u->L[  _0] |= 0x80000000L;
 179                 u->L[2+_0] |= 0x80000000L;
 180                 }
 181         return rv;
 182         }