g_xfmt.c revision 165744 
1/****************************************************************
2
3The author of this software is David M. Gay.
4
5Copyright (C) 1998 by Lucent Technologies
6All Rights Reserved
7
8Permission to use, copy, modify, and distribute this software and
9its documentation for any purpose and without fee is hereby
10granted, provided that the above copyright notice appear in all
11copies and that both that the copyright notice and this
12permission notice and warranty disclaimer appear in supporting
13documentation, and that the name of Lucent or any of its entities
14not be used in advertising or publicity pertaining to
15distribution of the software without specific, written prior
16permission.
17
18LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
25THIS 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
56g_xfmt(buf, V, ndig, bufsize) char *buf; char *V; int ndig; unsigned bufsize;
57#else
58g_xfmt(char *buf, void *V, int ndig, unsigned bufsize)
59#endif
60{
61	static FPI fpi = { 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
67	if (ndig < 0)
68		ndig = 0;
69	if (bufsize < ndig + 10)
70		return 0;
71
72	L = (UShort *)V;
73	sign = L[_0] & 0x8000;
74	bits[1] = (L[_1] << 16) | L[_2];
75	bits[0] = (L[_3] << 16) | L[_4];
76	if ( (ex = L[_0] & 0x7fff) !=0) {
77		if (ex == 0x7fff) {
78			/* Infinity or NaN */
79			if (bits[0] | bits[1])
80				b = strcp(buf, "NaN");
81			else {
82				b = buf;
83				if (sign)
84					*b++ = '-';
85				b = strcp(b, "Infinity");
86				}
87			return b;
88			}
89		i = STRTOG_Normal;
90		}
91	else if (bits[0] | bits[1]) {
92		i = STRTOG_Denormal;
93		ex = 1;
94		}
95	else {
96		b = buf;
97#ifndef IGNORE_ZERO_SIGN
98		if (sign)
99			*b++ = '-';
100#endif
101		*b++ = '0';
102		*b = 0;
103		return b;
104		}
105	ex -= 0x3fff + 63;
106	mode = 2;
107	if (ndig <= 0) {
108		if (bufsize < 32)
109			return 0;
110		mode = 0;
111		}
112	s = gdtoa(&fpi, ex, bits, &i, mode, ndig, &decpt, &se);
113	return g__fmt(buf, s, se, decpt, sign);
114	}
115