1*86d7f5d3SJohn Marino /*-
2*86d7f5d3SJohn Marino * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
3*86d7f5d3SJohn Marino * All rights reserved.
4*86d7f5d3SJohn Marino *
5*86d7f5d3SJohn Marino * Redistribution and use in source and binary forms, with or without
6*86d7f5d3SJohn Marino * modification, are permitted provided that the following conditions
7*86d7f5d3SJohn Marino * are met:
8*86d7f5d3SJohn Marino * 1. Redistributions of source code must retain the above copyright
9*86d7f5d3SJohn Marino * notice, this list of conditions and the following disclaimer.
10*86d7f5d3SJohn Marino * 2. Redistributions in binary form must reproduce the above copyright
11*86d7f5d3SJohn Marino * notice, this list of conditions and the following disclaimer in the
12*86d7f5d3SJohn Marino * documentation and/or other materials provided with the distribution.
13*86d7f5d3SJohn Marino *
14*86d7f5d3SJohn Marino * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*86d7f5d3SJohn Marino * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*86d7f5d3SJohn Marino * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*86d7f5d3SJohn Marino * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*86d7f5d3SJohn Marino * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*86d7f5d3SJohn Marino * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*86d7f5d3SJohn Marino * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*86d7f5d3SJohn Marino * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*86d7f5d3SJohn Marino * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*86d7f5d3SJohn Marino * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*86d7f5d3SJohn Marino * SUCH DAMAGE.
25*86d7f5d3SJohn Marino *
26*86d7f5d3SJohn Marino * $FreeBSD: src/lib/libc/gdtoa/_ldtoa.c,v 1.5 2007/12/09 19:48:57 das Exp $
27*86d7f5d3SJohn Marino */
28*86d7f5d3SJohn Marino
29*86d7f5d3SJohn Marino #include <float.h>
30*86d7f5d3SJohn Marino #include <inttypes.h>
31*86d7f5d3SJohn Marino #include <limits.h>
32*86d7f5d3SJohn Marino #include <math.h>
33*86d7f5d3SJohn Marino #include <stdlib.h>
34*86d7f5d3SJohn Marino #include "fpmath.h"
35*86d7f5d3SJohn Marino #include "gdtoaimp.h"
36*86d7f5d3SJohn Marino
37*86d7f5d3SJohn Marino /*
38*86d7f5d3SJohn Marino * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
39*86d7f5d3SJohn Marino * except that the floating point argument is passed by reference.
40*86d7f5d3SJohn Marino * When dtoa() is passed a NaN or infinity, it sets expt to 9999.
41*86d7f5d3SJohn Marino * However, a long double could have a valid exponent of 9999, so we
42*86d7f5d3SJohn Marino * use INT_MAX in ldtoa() instead.
43*86d7f5d3SJohn Marino */
44*86d7f5d3SJohn Marino char *
__ldtoa(long double * ld,int mode,int ndigits,int * decpt,int * sign,char ** rve)45*86d7f5d3SJohn Marino __ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign,
46*86d7f5d3SJohn Marino char **rve)
47*86d7f5d3SJohn Marino {
48*86d7f5d3SJohn Marino FPI fpi = {
49*86d7f5d3SJohn Marino LDBL_MANT_DIG, /* nbits */
50*86d7f5d3SJohn Marino LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */
51*86d7f5d3SJohn Marino LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */
52*86d7f5d3SJohn Marino FLT_ROUNDS, /* rounding */
53*86d7f5d3SJohn Marino #ifdef Sudden_Underflow /* unused, but correct anyway */
54*86d7f5d3SJohn Marino 1
55*86d7f5d3SJohn Marino #else
56*86d7f5d3SJohn Marino 0
57*86d7f5d3SJohn Marino #endif
58*86d7f5d3SJohn Marino };
59*86d7f5d3SJohn Marino int be, kind;
60*86d7f5d3SJohn Marino char *ret;
61*86d7f5d3SJohn Marino union IEEEl2bits u;
62*86d7f5d3SJohn Marino uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
63*86d7f5d3SJohn Marino void *vbits = bits;
64*86d7f5d3SJohn Marino
65*86d7f5d3SJohn Marino u.e = *ld;
66*86d7f5d3SJohn Marino
67*86d7f5d3SJohn Marino /*
68*86d7f5d3SJohn Marino * gdtoa doesn't know anything about the sign of the number, so
69*86d7f5d3SJohn Marino * if the number is negative, we need to swap rounding modes of
70*86d7f5d3SJohn Marino * 2 (upwards) and 3 (downwards).
71*86d7f5d3SJohn Marino */
72*86d7f5d3SJohn Marino *sign = u.bits.sign;
73*86d7f5d3SJohn Marino fpi.rounding ^= (fpi.rounding >> 1) & u.bits.sign;
74*86d7f5d3SJohn Marino
75*86d7f5d3SJohn Marino be = u.bits.exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1);
76*86d7f5d3SJohn Marino LDBL_TO_ARRAY32(u, bits);
77*86d7f5d3SJohn Marino
78*86d7f5d3SJohn Marino switch (fpclassify(u.e)) {
79*86d7f5d3SJohn Marino case FP_NORMAL:
80*86d7f5d3SJohn Marino kind = STRTOG_Normal;
81*86d7f5d3SJohn Marino #ifdef LDBL_IMPLICIT_NBIT
82*86d7f5d3SJohn Marino bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
83*86d7f5d3SJohn Marino #endif /* LDBL_IMPLICIT_NBIT */
84*86d7f5d3SJohn Marino break;
85*86d7f5d3SJohn Marino case FP_ZERO:
86*86d7f5d3SJohn Marino kind = STRTOG_Zero;
87*86d7f5d3SJohn Marino break;
88*86d7f5d3SJohn Marino case FP_SUBNORMAL:
89*86d7f5d3SJohn Marino kind = STRTOG_Denormal;
90*86d7f5d3SJohn Marino be++;
91*86d7f5d3SJohn Marino break;
92*86d7f5d3SJohn Marino case FP_INFINITE:
93*86d7f5d3SJohn Marino kind = STRTOG_Infinite;
94*86d7f5d3SJohn Marino break;
95*86d7f5d3SJohn Marino case FP_NAN:
96*86d7f5d3SJohn Marino kind = STRTOG_NaN;
97*86d7f5d3SJohn Marino break;
98*86d7f5d3SJohn Marino default:
99*86d7f5d3SJohn Marino abort();
100*86d7f5d3SJohn Marino }
101*86d7f5d3SJohn Marino
102*86d7f5d3SJohn Marino ret = gdtoa(&fpi, be, vbits, &kind, mode, ndigits, decpt, rve);
103*86d7f5d3SJohn Marino if (*decpt == -32768)
104*86d7f5d3SJohn Marino *decpt = INT_MAX;
105*86d7f5d3SJohn Marino return ret;
106*86d7f5d3SJohn Marino }
107