2 * Copyright (c) 2004-2008 David Schultz <das@FreeBSD.ORG>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
26 * $FreeBSD: src/lib/libc/gdtoa/_hldtoa.c,v 1.2 2008/04/12 14:53:52 das Exp $
38 #include "../stdio/floatio.h"
42 #if (LDBL_MANT_DIG > DBL_MANT_DIG)
44 /* Strings values used by dtoa() */
45 #define INFSTR "Infinity"
48 #ifdef LDBL_IMPLICIT_NBIT
49 #define MANH_SIZE LDBL_MANH_SIZE
51 #define MANH_SIZE (LDBL_MANH_SIZE - 1)
55 typedef uint64_t manh_t;
57 typedef uint32_t manh_t;
60 #if LDBL_MANL_SIZE > 32
61 typedef uint64_t manl_t;
63 typedef uint32_t manl_t;
66 #define LDBL_ADJ (LDBL_MAX_EXP - 2)
67 #define SIGFIGS ((LDBL_MANT_DIG + 3) / 4 + 1)
69 static const float one[] = { 1.0f, -1.0f };
72 * This is the long double version of __hdtoa().
75 __hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
90 switch (fpclassify(e)) {
92 *decpt = u.bits.exp - LDBL_ADJ;
96 return (nrv_alloc("0", rve, 1));
99 oldprec = fpsetprec(FP_PE);
102 *decpt = u.bits.exp - (514 + LDBL_ADJ);
109 return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
110 default: /* FP_NAN or unrecognized */
112 return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
115 /* FP_NORMAL or FP_SUBNORMAL */
117 if (ndigits == 0) /* dtoa() compatibility */
121 * If ndigits < 0, we are expected to auto-size, so we allocate
122 * enough space for all the digits.
124 bufsize = (ndigits > 0) ? ndigits : SIGFIGS;
125 s0 = rv_alloc(bufsize);
127 /* Round to the desired number of digits. */
128 if (SIGFIGS > ndigits && ndigits > 0) {
129 float redux = one[u.bits.sign];
130 int offset = 4 * ndigits + LDBL_MAX_EXP - 4 - LDBL_MANT_DIG;
132 oldprec = fpsetprec(FP_PE);
137 *decpt += u.bits.exp - offset;
147 for (s = s0 + 1; s < s0 + bufsize; s++) {
148 *s = xdigs[(manh >> (MANH_SIZE - 4)) & 0xf];
149 manh = (manh << 4) | (manl >> (LDBL_MANL_SIZE - 4));
153 /* If ndigits < 0, we are expected to auto-size the precision. */
155 for (ndigits = SIGFIGS; s0[ndigits - 1] == '0'; ndigits--)
166 #else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
169 __hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
173 return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
176 #endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */