lib/libc/gdtoa/strtoIg.c

   1 /* $NetBSD: strtoIg.c,v 1.1.1.1 2006/01/25 15:18:50 kleink Exp $ */
   2
   3 /****************************************************************
   4
   5 The author of this software is David M. Gay.
   6
   7 Copyright (C) 1998 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 strtoIg(s00, se, fpi, exp, B, rvp) CONST char *s00; char **se; FPI *fpi; Long *exp; Bigint **B; int *rvp;
  39 #else
  40 strtoIg(CONST char *s00, char **se, FPI *fpi, Long *exp, Bigint **B, int *rvp)
  41 #endif
  42 {
  43         Bigint *b, *b1;
  44         int i, nb, nw, nw1, rv, rv1, swap;
  45         unsigned int nb1, nb11;
  46         Long e1;
  47
  48         b = *B;
  49         rv = strtodg(s00, se, fpi, exp, b->x);
  50         if (rv == STRTOG_NoMemory)
  51                 return rv;
  52         if (!(rv & STRTOG_Inexact)) {
  53                 B[1] = 0;
  54                 return *rvp = rv;
  55                 }
  56         e1 = exp[0];
  57         rv1 = rv ^ STRTOG_Inexact;
  58         b1 = Balloc(b->k);
  59         if (b1 == NULL)
  60                 return STRTOG_NoMemory;
  61         Bcopy(b1, b);
  62         nb = fpi->nbits;
  63         nb1 = nb & 31;
  64         nb11 = (nb1 - 1) & 31;
  65         nw = b->wds;
  66         nw1 = nw - 1;
  67         if (rv & STRTOG_Inexlo) {
  68                 swap = 0;
  69                 b1 = increment(b1);
  70                 if (fpi->sudden_underflow
  71                  && (rv & STRTOG_Retmask) == STRTOG_Zero) {
  72                         b1->x[0] = 0;
  73                         b1->x[nw1] = 1L << nb11;
  74                         rv1 += STRTOG_Normal - STRTOG_Zero;
  75                         rv1 &= ~STRTOG_Underflow;
  76                         goto swapcheck;
  77                         }
  78                 if (b1->wds > nw
  79                  || nb1 && b1->x[nw1] & 1L << nb1) {
  80                         if (++e1 > fpi->emax)
  81                                 rv1 = STRTOG_Infinite | STRTOG_Inexhi;
  82                         rshift(b1, 1);
  83                         }
  84                 else if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
  85                         if (b1->x[nw1] & 1L << nb11) {
  86                                 rv1 += STRTOG_Normal - STRTOG_Denormal;
  87                                 rv1 &= ~STRTOG_Underflow;
  88                                 }
  89                         }
  90                 }
  91         else {
  92                 swap = STRTOG_Neg;
  93                 if ((rv & STRTOG_Retmask) == STRTOG_Infinite) {
  94                         b1 = set_ones(b1, nb);
  95                         e1 = fpi->emax;
  96                         rv1 = STRTOG_Normal | STRTOG_Inexlo;
  97                         goto swapcheck;
  98                         }
  99                 decrement(b1);
 100                 if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
 101                         for(i = nw1; !b1->x[i]; --i)
 102                                 if (!i) {
 103                                         rv1 = STRTOG_Zero | STRTOG_Inexlo;
 104                                         break;
 105                                         }
 106                         goto swapcheck;
 107                         }
 108                 if (!(b1->x[nw1] & 1L << nb11)) {
 109                         if (e1 == fpi->emin) {
 110                                 if (fpi->sudden_underflow)
 111                                         rv1 += STRTOG_Zero - STRTOG_Normal;
 112                                 else
 113                                         rv1 += STRTOG_Denormal - STRTOG_Normal;
 114                                 rv1 |= STRTOG_Underflow;
 115                                 }
 116                         else {
 117                                 b1 = lshift(b1, 1);
 118                                 b1->x[0] |= 1;
 119                                 --e1;
 120                                 }
 121                         }
 122                 }
 123  swapcheck:
 124         if (swap ^ (rv & STRTOG_Neg)) {
 125                 rvp[0] = rv1;
 126                 rvp[1] = rv;
 127                 B[0] = b1;
 128                 B[1] = b;
 129                 exp[1] = exp[0];
 130                 exp[0] = e1;
 131                 }
 132         else {
 133                 rvp[0] = rv;
 134                 rvp[1] = rv1;
 135                 B[1] = b1;
 136                 exp[1] = e1;
 137                 }
 138         return rv;
 139         }