1 /* $NetBSD: ldtoa.c,v 1.4.2.1 2007/05/07 19:49:06 pavel Exp $ */
2
3 /*-
4 * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 #include <LibConfig.h>
29 #include <sys/EfiCdefs.h>
30
31 #include <float.h>
32 #include <inttypes.h>
33 #include <limits.h>
34 #include <math.h>
35 #include <stdlib.h>
36 #include <machine/ieee.h>
37 #include "gdtoaimp.h"
38
39 #if defined(_MSC_VER)
40 /* Disable warnings about conversions to narrower data types,
41 primarily for the fpclassify() macro.
42 */
43 #pragma warning ( disable : 4244 )
44 // Squelch bogus warnings about uninitialized variable use.
45 #pragma warning ( disable : 4700 )
46 #endif
47
48 /*
49 * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
50 * except that the floating point argument is passed by reference.
51 * When dtoa() is passed a NaN or infinity, it sets expt to 9999.
52 * However, a long double could have a valid exponent of 9999, so we
53 * use INT_MAX in ldtoa() instead.
54 */
55 char *
ldtoa(long double * ld,int mode,int ndigits,int * decpt,int * sign,char ** rve)56 ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, char **rve)
57 {
58 #ifdef EXT_EXPBITS
59 static FPI fpi = {
60 LDBL_MANT_DIG, /* nbits */
61 LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */
62 LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */
63 FPI_Round_near, /* rounding */
64 #ifdef Sudden_Underflow /* unused, but correct anyway */
65 1
66 #else
67 0
68 #endif
69 };
70 int be, kind;
71 char *ret;
72 union ieee_ext_u u;
73 uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
74
75 u.extu_ld = *ld;
76 *sign = (int)(u.extu_ext.ext_sign);
77 be = (int)(u.extu_ext.ext_exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1));
78 EXT_TO_ARRAY32(u, bits);
79
80 switch (fpclassify(u.extu_ld)) {
81 case FP_NORMAL:
82 kind = STRTOG_Normal;
83 #ifdef LDBL_IMPLICIT_NBIT
84 bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
85 #endif /* LDBL_IMPLICIT_NBIT */
86 break;
87 case FP_ZERO:
88 kind = STRTOG_Zero;
89 break;
90 case FP_SUBNORMAL:
91 kind = STRTOG_Denormal;
92 #ifdef LDBL_IMPLICIT_NBIT
93 be++;
94 #endif
95 break;
96 case FP_INFINITE:
97 kind = STRTOG_Infinite;
98 break;
99 case FP_NAN:
100 kind = STRTOG_NaN;
101 break;
102 default:
103 abort();
104 }
105
106 ret = gdtoa(&fpi, be, (ULong *)bits, &kind, mode, ndigits, decpt, rve);
107 if (*decpt == -32768)
108 *decpt = INT_MAX;
109 return ret;
110 #else
111 return dtoa((double)*ld, mode, ndigits, decpt, sign, rve);
112 #endif
113 }
114