1/*-
2 * Copyright (c) 2004-2008 David Schultz <das@FreeBSD.ORG>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <float.h>
31#include <limits.h>
32#include <math.h>
33#include <stdint.h>
34
35#ifdef __i386__
36#include <ieeefp.h>
37#endif
38
39#include "../stdio/floatio.h"
40#include "fpmath.h"
41#include "gdtoaimp.h"
42
43#if (LDBL_MANT_DIG > DBL_MANT_DIG)
44
45/* Strings values used by dtoa() */
46#define	INFSTR	"Infinity"
47#define	NANSTR	"NaN"
48
49#ifdef LDBL_IMPLICIT_NBIT
50#define	MANH_SIZE	LDBL_MANH_SIZE
51#else
52#define	MANH_SIZE	(LDBL_MANH_SIZE - 1)
53#endif
54
55#if MANH_SIZE > 32
56typedef uint64_t manh_t;
57#else
58typedef uint32_t manh_t;
59#endif
60
61#if LDBL_MANL_SIZE > 32
62typedef uint64_t manl_t;
63#else
64typedef uint32_t manl_t;
65#endif
66
67#define	LDBL_ADJ	(LDBL_MAX_EXP - 2)
68#define	SIGFIGS		((LDBL_MANT_DIG + 3) / 4 + 1)
69
70static const float one[] = { 1.0f, -1.0f };
71
72/*
73 * This is the long double version of __hdtoa().
74 */
75char *
76__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
77    char **rve)
78{
79	union IEEEl2bits u;
80	char *s, *s0;
81	manh_t manh;
82	manl_t manl;
83	int bufsize;
84#ifdef __i386__
85	fp_prec_t oldprec;
86#endif
87
88	u.e = e;
89	*sign = u.bits.sign;
90
91	switch (fpclassify(e)) {
92	case FP_NORMAL:
93		*decpt = u.bits.exp - LDBL_ADJ;
94		break;
95	case FP_ZERO:
96		*decpt = 1;
97		return (nrv_alloc("0", rve, 1));
98	case FP_SUBNORMAL:
99#ifdef __i386__
100		oldprec = fpsetprec(FP_PE);
101#endif
102		u.e *= 0x1p514L;
103		*decpt = u.bits.exp - (514 + LDBL_ADJ);
104#ifdef __i386__
105		fpsetprec(oldprec);
106#endif
107		break;
108	case FP_INFINITE:
109		*decpt = INT_MAX;
110		return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
111	default:	/* FP_NAN or unrecognized */
112		*decpt = INT_MAX;
113		return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
114	}
115
116	/* FP_NORMAL or FP_SUBNORMAL */
117
118	if (ndigits == 0)		/* dtoa() compatibility */
119		ndigits = 1;
120
121	/*
122	 * If ndigits < 0, we are expected to auto-size, so we allocate
123	 * enough space for all the digits.
124	 */
125	bufsize = (ndigits > 0) ? ndigits : SIGFIGS;
126	s0 = rv_alloc(bufsize);
127
128	/* Round to the desired number of digits. */
129	if (SIGFIGS > ndigits && ndigits > 0) {
130		float redux = one[u.bits.sign];
131		int offset = 4 * ndigits + LDBL_MAX_EXP - 4 - LDBL_MANT_DIG;
132#ifdef __i386__
133		oldprec = fpsetprec(FP_PE);
134#endif
135		u.bits.exp = offset;
136		u.e += redux;
137		u.e -= redux;
138		*decpt += u.bits.exp - offset;
139#ifdef __i386__
140		fpsetprec(oldprec);
141#endif
142	}
143
144	mask_nbit_l(u);
145	manh = u.bits.manh;
146	manl = u.bits.manl;
147	*s0 = '1';
148	for (s = s0 + 1; s < s0 + bufsize; s++) {
149		*s = xdigs[(manh >> (MANH_SIZE - 4)) & 0xf];
150		manh = (manh << 4) | (manl >> (LDBL_MANL_SIZE - 4));
151		manl <<= 4;
152	}
153
154	/* If ndigits < 0, we are expected to auto-size the precision. */
155	if (ndigits < 0) {
156		for (ndigits = SIGFIGS; s0[ndigits - 1] == '0'; ndigits--)
157			;
158	}
159
160	s = s0 + ndigits;
161	*s = '\0';
162	if (rve != NULL)
163		*rve = s;
164	return (s0);
165}
166
167#else	/* (LDBL_MANT_DIG == DBL_MANT_DIG) */
168
169char *
170__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
171    char **rve)
172{
173
174	return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
175}
176
177#endif	/* (LDBL_MANT_DIG == DBL_MANT_DIG) */
178