gdtoa/FreeBSD/gdtoa-strtoIg.c

   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 David M. Gay (dmg at acm dot org,
  30  * with " at " changed at "@" and " dot " changed to ".").      */
  31
  32 #include "gdtoaimp.h"
  33
  34  int
  35 #ifdef KR_headers
  36 strtoIg(s00, se, fpi, exp, B, rvp) CONST char *s00; char **se; FPI *fpi; Long *exp; Bigint **B; int *rvp;
  37 #else
  38 strtoIg(CONST char *s00, char **se, FPI *fpi, Long *exp, Bigint **B, int *rvp)
  39 #endif
  40 {
  41         Bigint *b, *b1;
  42         int i, nb, nw, nw1, rv, rv1, swap;
  43         unsigned int nb1, nb11;
  44         Long e1;
  45
  46         b = *B;
  47         rv = strtodg(s00, se, fpi, exp, b->x);
  48         if (!(rv & STRTOG_Inexact)) {
  49                 B[1] = 0;
  50                 return *rvp = rv;
  51                 }
  52         e1 = exp[0];
  53         rv1 = rv ^ STRTOG_Inexact;
  54         b1 = Balloc(b->k);
  55         Bcopy(b1, b);
  56         nb = fpi->nbits;
  57         nb1 = nb & 31;
  58         nb11 = (nb1 - 1) & 31;
  59         nw = b->wds;
  60         nw1 = nw - 1;
  61         if (rv & STRTOG_Inexlo) {
  62                 swap = 0;
  63                 b1 = increment(b1);
  64                 if (fpi->sudden_underflow
  65                  && (rv & STRTOG_Retmask) == STRTOG_Zero) {
  66                         b1->x[0] = 0;
  67                         b1->x[nw1] = 1L << nb11;
  68                         rv1 += STRTOG_Normal - STRTOG_Zero;
  69                         rv1 &= ~STRTOG_Underflow;
  70                         goto swapcheck;
  71                         }
  72                 if (b1->wds > nw
  73                  || nb1 && b1->x[nw1] & 1L << nb1) {
  74                         if (++e1 > fpi->emax)
  75                                 rv1 = STRTOG_Infinite | STRTOG_Inexhi;
  76                         rshift(b1, 1);
  77                         }
  78                 else if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
  79                         if (b1->x[nw1] & 1L << nb11) {
  80                                 rv1 += STRTOG_Normal - STRTOG_Denormal;
  81                                 rv1 &= ~STRTOG_Underflow;
  82                                 }
  83                         }
  84                 }
  85         else {
  86                 swap = STRTOG_Neg;
  87                 if ((rv & STRTOG_Retmask) == STRTOG_Infinite) {
  88                         b1 = set_ones(b1, nb);
  89                         e1 = fpi->emax;
  90                         rv1 = STRTOG_Normal | STRTOG_Inexlo;
  91                         goto swapcheck;
  92                         }
  93                 decrement(b1);
  94                 if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
  95                         for(i = nw1; !b1->x[i]; --i)
  96                                 if (!i) {
  97                                         rv1 = STRTOG_Zero | STRTOG_Inexlo;
  98                                         break;
  99                                         }
 100                         goto swapcheck;
 101                         }
 102                 if (!(b1->x[nw1] & 1L << nb11)) {
 103                         if (e1 == fpi->emin) {
 104                                 if (fpi->sudden_underflow)
 105                                         rv1 += STRTOG_Zero - STRTOG_Normal;
 106                                 else
 107                                         rv1 += STRTOG_Denormal - STRTOG_Normal;
 108                                 rv1 |= STRTOG_Underflow;
 109                                 }
 110                         else {
 111                                 b1 = lshift(b1, 1);
 112                                 b1->x[0] |= 1;
 113                                 --e1;
 114                                 }
 115                         }
 116                 }
 117  swapcheck:
 118         if (swap ^ (rv & STRTOG_Neg)) {
 119                 rvp[0] = rv1;
 120                 rvp[1] = rv;
 121                 B[0] = b1;
 122                 B[1] = b;
 123                 exp[1] = exp[0];
 124                 exp[0] = e1;
 125                 }
 126         else {
 127                 rvp[0] = rv;
 128                 rvp[1] = rv1;
 129                 B[1] = b1;
 130                 exp[1] = e1;
 131                 }
 132         return rv;
 133         }