contrib/gdtoa/g_xfmt.c

   1 /****************************************************************
   2
   3 The author of this software is David M. Gay.
   4
   5 Copyright (C) 1998 by Lucent Technologies
   6 All Rights Reserved
   7
   8 Permission to use, copy, modify, and distribute this software and
   9 its documentation for any purpose and without fee is hereby
  10 granted, provided that the above copyright notice appear in all
  11 copies and that both that the copyright notice and this
  12 permission notice and warranty disclaimer appear in supporting
  13 documentation, and that the name of Lucent or any of its entities
  14 not be used in advertising or publicity pertaining to
  15 distribution of the software without specific, written prior
  16 permission.
  17
  18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
  20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
  21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
  23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
  25 THIS SOFTWARE.
  26
  27 ****************************************************************/
  28
  29 /* Please send bug reports to David M. Gay (dmg at acm dot org,
  30  * with " at " changed at "@" and " dot " changed to ".").      */
  31
  32 #include "gdtoaimp.h"
  33
  34 #undef _0
  35 #undef _1
  36
  37 /* one or the other of IEEE_MC68k or IEEE_8087 should be #defined */
  38
  39 #ifdef IEEE_MC68k
  40 #define _0 0
  41 #define _1 1
  42 #define _2 2
  43 #define _3 3
  44 #define _4 4
  45 #endif
  46 #ifdef IEEE_8087
  47 #define _0 4
  48 #define _1 3
  49 #define _2 2
  50 #define _3 1
  51 #define _4 0
  52 #endif
  53
  54  char*
  55 #ifdef KR_headers
  56 g_xfmt(buf, V, ndig, bufsize) char *buf; char *V; int ndig; size_t bufsize;
  57 #else
  58 g_xfmt(char *buf, void *V, int ndig, size_t bufsize)
  59 #endif
  60 {
  61         static FPI fpi0 = { 64, 1-16383-64+1, 32766 - 16383 - 64 + 1, 1, 0 };
  62         char *b, *s, *se;
  63         ULong bits[2], sign;
  64         UShort *L;
  65         int decpt, ex, i, mode;
  66 #ifdef Honor_FLT_ROUNDS
  67 #include "gdtoa_fltrnds.h"
  68 #else
  69 #define fpi &fpi0
  70 #endif
  71
  72         if (ndig < 0)
  73                 ndig = 0;
  74         if (bufsize < ndig + 10)
  75                 return 0;
  76
  77         L = (UShort *)V;
  78         sign = L[_0] & 0x8000;
  79         bits[1] = (L[_1] << 16) | L[_2];
  80         bits[0] = (L[_3] << 16) | L[_4];
  81         if ( (ex = L[_0] & 0x7fff) !=0) {
  82                 if (ex == 0x7fff) {
  83                         /* Infinity or NaN */
  84                         if (bits[0] | bits[1])
  85                                 b = strcp(buf, "NaN");
  86                         else {
  87                                 b = buf;
  88                                 if (sign)
  89                                         *b++ = '-';
  90                                 b = strcp(b, "Infinity");
  91                                 }
  92                         return b;
  93                         }
  94                 i = STRTOG_Normal;
  95                 }
  96         else if (bits[0] | bits[1]) {
  97                 i = STRTOG_Denormal;
  98                 ex = 1;
  99                 }
 100         else {
 101                 b = buf;
 102 #ifndef IGNORE_ZERO_SIGN
 103                 if (sign)
 104                         *b++ = '-';
 105 #endif
 106                 *b++ = '0';
 107                 *b = 0;
 108                 return b;
 109                 }
 110         ex -= 0x3fff + 63;
 111         mode = 2;
 112         if (ndig <= 0) {
 113                 if (bufsize < 32)
 114                         return 0;
 115                 mode = 0;
 116                 }
 117         s = gdtoa(fpi, ex, bits, &i, mode, ndig, &decpt, &se);
 118         return g__fmt(buf, s, se, decpt, sign, bufsize);
 119         }