lib/libc/gdtoa/g_xfmt.c

   1 /* $NetBSD: g_xfmt.c,v 1.4 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 #undef _0
  37 #undef _1
  38
  39 /* one or the other of IEEE_BIG_ENDIAN or IEEE_LITTLE_ENDIAN should be #defined */
  40
  41 #ifdef IEEE_BIG_ENDIAN
  42 #define _0 0
  43 #define _1 1
  44 #define _2 2
  45 #define _3 3
  46 #define _4 4
  47 #endif
  48 #ifdef IEEE_LITTLE_ENDIAN
  49 #define _0 4
  50 #define _1 3
  51 #define _2 2
  52 #define _3 1
  53 #define _4 0
  54 #endif
  55
  56  char*
  57 #ifdef KR_headers
  58 g_xfmt(buf, V, ndig, bufsize) char *buf; char *V; int ndig; size_t bufsize;
  59 #else
  60 g_xfmt(char *buf, void *V, int ndig, size_t bufsize)
  61 #endif
  62 {
  63         static FPI fpi0 = { 64, 1-16383-64+1, 32766 - 16383 - 64 + 1, 1, 0 };
  64         char *b, *s, *se;
  65         ULong bits[2], sign;
  66         UShort *L;
  67         int decpt, ex, i, mode;
  68 #ifdef Honor_FLT_ROUNDS
  69 #include "gdtoa_fltrnds.h"
  70 #else
  71 #define fpi &fpi0
  72 #endif
  73
  74         if (ndig < 0)
  75                 ndig = 0;
  76         if (bufsize < ndig + 10)
  77                 return 0;
  78
  79         L = (UShort *)V;
  80         sign = L[_0] & 0x8000;
  81         bits[1] = (L[_1] << 16) | L[_2];
  82         bits[0] = (L[_3] << 16) | L[_4];
  83         if ( (ex = L[_0] & 0x7fff) !=0) {
  84                 if (ex == 0x7fff) {
  85                         /* Infinity or NaN */
  86                         if (bits[0] | bits[1])
  87                                 b = strcp(buf, "NaN");
  88                         else {
  89                                 b = buf;
  90                                 if (sign)
  91                                         *b++ = '-';
  92                                 b = strcp(b, "Infinity");
  93                                 }
  94                         return b;
  95                         }
  96                 i = STRTOG_Normal;
  97                 }
  98         else if (bits[0] | bits[1]) {
  99                 i = STRTOG_Denormal;
 100                 ex = 1;
 101                 }
 102         else {
 103                 b = buf;
 104 #ifndef IGNORE_ZERO_SIGN
 105                 if (sign)
 106                         *b++ = '-';
 107 #endif
 108                 *b++ = '0';
 109                 *b = 0;
 110                 return b;
 111                 }
 112         ex -= 0x3fff + 63;
 113         mode = 2;
 114         if (ndig <= 0) {
 115                 if (bufsize < 32)
 116                         return 0;
 117                 mode = 0;
 118                 }
 119         s = gdtoa(fpi, ex, bits, &i, mode, ndig, &decpt, &se);
 120         if (s == NULL)
 121                 return NULL;
 122         return g__fmt(buf, s, se, decpt, sign, bufsize);
 123         }