lib/libc/gdtoa/strtoIg.c

   1 /* $NetBSD: strtoIg.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 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 ((rv & STRTOG_Retmask) == STRTOG_Zero) {
  71                         if (fpi->sudden_underflow) {
  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                         rv1 &= STRTOG_Inexlo | STRTOG_Underflow | STRTOG_Zero;
  79                         rv1 |= STRTOG_Inexhi | STRTOG_Denormal;
  80                         goto swapcheck;
  81                         }
  82                 if (b1->wds > nw
  83                  || (nb1 && b1->x[nw1] & 1L << nb1)) {
  84                         if (++e1 > fpi->emax)
  85                                 rv1 = STRTOG_Infinite | STRTOG_Inexhi;
  86                         rshift(b1, 1);
  87                         }
  88                 else if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
  89                         if (b1->x[nw1] & 1L << nb11) {
  90                                 rv1 += STRTOG_Normal - STRTOG_Denormal;
  91                                 rv1 &= ~STRTOG_Underflow;
  92                                 }
  93                         }
  94                 }
  95         else {
  96                 swap = STRTOG_Neg;
  97                 if ((rv & STRTOG_Retmask) == STRTOG_Infinite) {
  98                         b1 = set_ones(b1, nb);
  99                         e1 = fpi->emax;
 100                         rv1 = STRTOG_Normal | STRTOG_Inexlo;
 101                         goto swapcheck;
 102                         }
 103                 decrement(b1);
 104                 if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
 105                         for(i = nw1; !b1->x[i]; --i)
 106                                 if (!i) {
 107                                         rv1 = STRTOG_Zero | STRTOG_Inexlo;
 108                                         break;
 109                                         }
 110                         goto swapcheck;
 111                         }
 112                 if (!(b1->x[nw1] & 1L << nb11)) {
 113                         if (e1 == fpi->emin) {
 114                                 if (fpi->sudden_underflow)
 115                                         rv1 += STRTOG_Zero - STRTOG_Normal;
 116                                 else
 117                                         rv1 += STRTOG_Denormal - STRTOG_Normal;
 118                                 rv1 |= STRTOG_Underflow;
 119                                 }
 120                         else {
 121                                 b1 = lshift(b1, 1);
 122                                 b1->x[0] |= 1;
 123                                 --e1;
 124                                 }
 125                         }
 126                 }
 127  swapcheck:
 128         if (swap ^ (rv & STRTOG_Neg)) {
 129                 rvp[0] = rv1;
 130                 rvp[1] = rv;
 131                 B[0] = b1;
 132                 B[1] = b;
 133                 exp[1] = exp[0];
 134                 exp[0] = e1;
 135                 }
 136         else {
 137                 rvp[0] = rv;
 138                 rvp[1] = rv1;
 139                 B[1] = b1;
 140                 exp[1] = e1;
 141                 }
 142         return rv;
 143         }