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@acm.org). */
30
31#include "gdtoaimp.h"
32#include <string.h>
33
34 char *
35#ifdef KR_headers
36g_ddfmt(buf, dd0, ndig, bufsize) char *buf; double *dd0; int ndig; size_t bufsize;
37#else
38g_ddfmt(char *buf, double *dd0, int ndig, size_t bufsize)
39#endif
40{
41	FPI fpi;
42	char *b, *s, *se;
43	ULong *L, bits0[4], *bits, *zx;
44	int bx, by, decpt, ex, ey, i, j, mode;
45	Bigint *x, *y, *z;
46	U *dd, ddx[2];
47#ifdef Honor_FLT_ROUNDS /*{{*/
48	int Rounding;
49#ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */
50	Rounding = Flt_Rounds;
51#else /*}{*/
52	Rounding = 1;
53	switch(fegetround()) {
54	  case FE_TOWARDZERO:	Rounding = 0; break;
55	  case FE_UPWARD:	Rounding = 2; break;
56	  case FE_DOWNWARD:	Rounding = 3;
57	  }
58#endif /*}}*/
59#else /*}{*/
60#define Rounding FPI_Round_near
61#endif /*}}*/
62
63	if (bufsize < 10 || bufsize < ndig + 8)
64		return 0;
65
66	dd = (U*)dd0;
67	L = dd->L;
68	if ((L[_0] & 0x7ff00000L) == 0x7ff00000L) {
69		/* Infinity or NaN */
70		if (L[_0] & 0xfffff || L[_1]) {
71 nanret:
72			return strcp(buf, "NaN");
73			}
74		if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) {
75			if (L[2+_0] & 0xfffff || L[2+_1])
76				goto nanret;
77			if ((L[_0] ^ L[2+_0]) & 0x80000000L)
78				goto nanret;	/* Infinity - Infinity */
79			}
80 infret:
81		b = buf;
82		if (L[_0] & 0x80000000L)
83			*b++ = '-';
84		return strcp(b, "Infinity");
85		}
86	if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) {
87		L += 2;
88		if (L[_0] & 0xfffff || L[_1])
89			goto nanret;
90		goto infret;
91		}
92	if (dval(&dd[0]) + dval(&dd[1]) == 0.) {
93		b = buf;
94#ifndef IGNORE_ZERO_SIGN
95		if (L[_0] & L[2+_0] & 0x80000000L)
96			*b++ = '-';
97#endif
98		*b++ = '0';
99		*b = 0;
100		return b;
101		}
102	if ((L[_0] & 0x7ff00000L) < (L[2+_0] & 0x7ff00000L)) {
103		dval(&ddx[1]) = dval(&dd[0]);
104		dval(&ddx[0]) = dval(&dd[1]);
105		dd = ddx;
106		L = dd->L;
107		}
108	z = d2b(dval(&dd[0]), &ex, &bx);
109	if (dval(&dd[1]) == 0.)
110		goto no_y;
111	x = z;
112	y = d2b(dval(&dd[1]), &ey, &by);
113	if ( (i = ex - ey) !=0) {
114		if (i > 0) {
115			x = lshift(x, i);
116			ex = ey;
117			}
118		else
119			y = lshift(y, -i);
120		}
121	if ((L[_0] ^ L[2+_0]) & 0x80000000L) {
122		z = diff(x, y);
123		if (L[_0] & 0x80000000L)
124			z->sign = 1 - z->sign;
125		}
126	else {
127		z = sum(x, y);
128		if (L[_0] & 0x80000000L)
129			z->sign = 1;
130		}
131	Bfree(x);
132	Bfree(y);
133 no_y:
134	bits = zx = z->x;
135	for(i = 0; !*zx; zx++)
136		i += 32;
137	i += lo0bits(zx);
138	if (i) {
139		rshift(z, i);
140		ex += i;
141		}
142	fpi.nbits = z->wds * 32 - hi0bits(z->x[j = z->wds-1]);
143	if (fpi.nbits < 106) {
144		fpi.nbits = 106;
145		if (j < 3) {
146			for(i = 0; i <= j; i++)
147				bits0[i] = bits[i];
148			while(i < 4)
149				bits0[i++] = 0;
150			bits = bits0;
151			}
152		}
153	mode = 2;
154	if (ndig <= 0) {
155		if (bufsize < (int)(fpi.nbits * .301029995664) + 10) {
156			Bfree(z);
157			return 0;
158			}
159		mode = 0;
160		}
161	fpi.emin = 1-1023-53+1;
162	fpi.emax = 2046-1023-106+1;
163	fpi.rounding = Rounding;
164	fpi.sudden_underflow = 0;
165	i = STRTOG_Normal;
166	s = gdtoa(&fpi, ex, bits, &i, mode, ndig, &decpt, &se);
167	b = g__fmt(buf, s, se, decpt, z->sign, bufsize);
168	Bfree(z);
169	return b;
170	}
171