xref: /minix/lib/libc/gdtoa/g_xLfmt.c (revision 83ee113e)
1 /* $NetBSD: g_xLfmt.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 #endif
46 #ifdef IEEE_LITTLE_ENDIAN
47 #define _0 2
48 #define _1 1
49 #define _2 0
50 #endif
51 
52  char*
53 #ifdef KR_headers
54 g_xLfmt(buf, V, ndig, bufsize) char *buf; char *V; int ndig; size_t bufsize;
55 #else
56 g_xLfmt(char *buf, void *V, int ndig, size_t bufsize)
57 #endif
58 {
59 	static FPI fpi0 = { 64, 1-16383-64+1, 32766 - 16383 - 64 + 1, 1, 0 };
60 	char *b, *s, *se;
61 	ULong bits[2], *L, sign;
62 	int decpt, ex, i, mode;
63 #ifdef Honor_FLT_ROUNDS
64 #include "gdtoa_fltrnds.h"
65 #else
66 #define fpi &fpi0
67 #endif
68 
69 	if (ndig < 0)
70 		ndig = 0;
71 	if (bufsize < ndig + 10)
72 		return 0;
73 
74 	L = (ULong*)V;
75 	sign = L[_0] & 0x80000000L;
76 	bits[1] = L[_1];
77 	bits[0] = L[_2];
78 	if ( (ex = (L[_0] >> 16) & 0x7fff) !=0) {
79 		if (ex == 0x7fff) {
80 			/* Infinity or NaN */
81 			if (bits[0] | bits[1])
82 				b = strcp(buf, "NaN");
83 			else {
84 				b = buf;
85 				if (sign)
86 					*b++ = '-';
87 				b = strcp(b, "Infinity");
88 				}
89 			return b;
90 			}
91 		i = STRTOG_Normal;
92 		}
93 	else if (bits[0] | bits[1]) {
94 		i = STRTOG_Denormal;
95 		}
96 	else {
97 		b = buf;
98 #ifndef IGNORE_ZERO_SIGN
99 		if (sign)
100 			*b++ = '-';
101 #endif
102 		*b++ = '0';
103 		*b = 0;
104 		return b;
105 		}
106 	ex -= 0x3fff + 63;
107 	mode = 2;
108 	if (ndig <= 0) {
109 		if (bufsize < 32)
110 			return 0;
111 		mode = 0;
112 		}
113 	s = gdtoa(fpi, ex, bits, &i, mode, ndig, &decpt, &se);
114 	if (s == NULL)
115 		return NULL;
116 	return g__fmt(buf, s, se, decpt, sign, bufsize);
117 	}
118