StdLib/LibC/gdtoa/hexnan.c

   1 /* $NetBSD: hexnan.c,v 1.3 2006/03/11 18:38:14 kleink Exp $ */
   2
   3 /****************************************************************
   4
   5 The author of this software is David M. Gay.
   6
   7 Copyright (C) 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 #include  <LibConfig.h>
  34
  35 #include "gdtoaimp.h"
  36
  37  static void
  38 #ifdef KR_headers
  39 L_shift(x, x1, i) ULong *x; ULong *x1; int i;
  40 #else
  41 L_shift(ULong *x, ULong *x1, int i)
  42 #endif
  43 {
  44   int j;
  45
  46   i = 8 - i;
  47   i <<= 2;
  48   j = ULbits - i;
  49   do {
  50     *x |= x[1] << j;
  51     x[1] >>= i;
  52     } while(++x < x1);
  53   }
  54
  55  int
  56 #ifdef KR_headers
  57 hexnan(sp, fpi, x0)
  58   CONST char **sp; CONST FPI *fpi; ULong *x0;
  59 #else
  60 hexnan( CONST char **sp, CONST FPI *fpi, ULong *x0)
  61 #endif
  62 {
  63   ULong c, h, *x, *x1, *xe;
  64   CONST char *s;
  65   int havedig, hd0, i, nbits;
  66
  67   if (!hexdig['0'])
  68     hexdig_init_D2A();
  69   nbits = fpi->nbits;
  70   x = x0 + ((unsigned int)nbits >> kshift);
  71   if (nbits & kmask)
  72     x++;
  73   *--x = 0;
  74   x1 = xe = x;
  75   havedig = hd0 = i = 0;
  76   s = *sp;
  77   while((c = *(CONST unsigned char*)++s) != 0) {
  78     if ((h = hexdig[c]) == 0) {
  79       if (c <= ' ') {
  80         if (hd0 < havedig) {
  81           if (x < x1 && i < 8)
  82             L_shift(x, x1, i);
  83           if (x <= x0) {
  84             i = 8;
  85             continue;
  86             }
  87           hd0 = havedig;
  88           *--x = 0;
  89           x1 = x;
  90           i = 0;
  91           }
  92         continue;
  93         }
  94       if (/*(*/ c == ')' && havedig) {
  95         *sp = s + 1;
  96         break;
  97         }
  98       return STRTOG_NaN;
  99       }
 100     havedig++;
 101     if (++i > 8) {
 102       if (x <= x0)
 103         continue;
 104       i = 1;
 105       *--x = 0;
 106       }
 107     *x = (*x << 4) | (h & 0xf);
 108     }
 109   if (!havedig)
 110     return STRTOG_NaN;
 111   if (x < x1 && i < 8)
 112     L_shift(x, x1, i);
 113   if (x > x0) {
 114     x1 = x0;
 115     do *x1++ = *x++;
 116       while(x <= xe);
 117     do *x1++ = 0;
 118       while(x1 <= xe);
 119     }
 120   else {
 121     /* truncate high-order word if necessary */
 122     if ( (i = nbits & (ULbits-1)) !=0)
 123       *xe &= ((ULong)0xffffffff) >> (ULbits - i);
 124     }
 125   for(x1 = xe;; --x1) {
 126     if (*x1 != 0)
 127       break;
 128     if (x1 == x0) {
 129       *x1 = 1;
 130       break;
 131       }
 132     }
 133   return STRTOG_NaNbits;
 134   }