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