freebsd-dev/lib/libc/gdtoa/_hldtoa.c
Pedro F. Giffuni d915a14ef0 libc: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-25 17:12:48 +00:00

180 lines
4.4 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2004-2008 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdint.h>
#ifdef __i386__
#include <ieeefp.h>
#endif
#include "../stdio/floatio.h"
#include "fpmath.h"
#include "gdtoaimp.h"
#if (LDBL_MANT_DIG > DBL_MANT_DIG)
/* Strings values used by dtoa() */
#define INFSTR "Infinity"
#define NANSTR "NaN"
#ifdef LDBL_IMPLICIT_NBIT
#define MANH_SIZE LDBL_MANH_SIZE
#else
#define MANH_SIZE (LDBL_MANH_SIZE - 1)
#endif
#if MANH_SIZE > 32
typedef uint64_t manh_t;
#else
typedef uint32_t manh_t;
#endif
#if LDBL_MANL_SIZE > 32
typedef uint64_t manl_t;
#else
typedef uint32_t manl_t;
#endif
#define LDBL_ADJ (LDBL_MAX_EXP - 2)
#define SIGFIGS ((LDBL_MANT_DIG + 3) / 4 + 1)
static const float one[] = { 1.0f, -1.0f };
/*
* This is the long double version of __hdtoa().
*/
char *
__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
union IEEEl2bits u;
char *s, *s0;
manh_t manh;
manl_t manl;
int bufsize;
#ifdef __i386__
fp_prec_t oldprec;
#endif
u.e = e;
*sign = u.bits.sign;
switch (fpclassify(e)) {
case FP_NORMAL:
*decpt = u.bits.exp - LDBL_ADJ;
break;
case FP_ZERO:
*decpt = 1;
return (nrv_alloc("0", rve, 1));
case FP_SUBNORMAL:
#ifdef __i386__
oldprec = fpsetprec(FP_PE);
#endif
u.e *= 0x1p514L;
*decpt = u.bits.exp - (514 + LDBL_ADJ);
#ifdef __i386__
fpsetprec(oldprec);
#endif
break;
case FP_INFINITE:
*decpt = INT_MAX;
return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
default: /* FP_NAN or unrecognized */
*decpt = INT_MAX;
return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
}
/* FP_NORMAL or FP_SUBNORMAL */
if (ndigits == 0) /* dtoa() compatibility */
ndigits = 1;
/*
* If ndigits < 0, we are expected to auto-size, so we allocate
* enough space for all the digits.
*/
bufsize = (ndigits > 0) ? ndigits : SIGFIGS;
s0 = rv_alloc(bufsize);
/* Round to the desired number of digits. */
if (SIGFIGS > ndigits && ndigits > 0) {
float redux = one[u.bits.sign];
int offset = 4 * ndigits + LDBL_MAX_EXP - 4 - LDBL_MANT_DIG;
#ifdef __i386__
oldprec = fpsetprec(FP_PE);
#endif
u.bits.exp = offset;
u.e += redux;
u.e -= redux;
*decpt += u.bits.exp - offset;
#ifdef __i386__
fpsetprec(oldprec);
#endif
}
mask_nbit_l(u);
manh = u.bits.manh;
manl = u.bits.manl;
*s0 = '1';
for (s = s0 + 1; s < s0 + bufsize; s++) {
*s = xdigs[(manh >> (MANH_SIZE - 4)) & 0xf];
manh = (manh << 4) | (manl >> (LDBL_MANL_SIZE - 4));
manl <<= 4;
}
/* If ndigits < 0, we are expected to auto-size the precision. */
if (ndigits < 0) {
for (ndigits = SIGFIGS; s0[ndigits - 1] == '0'; ndigits--)
;
}
s = s0 + ndigits;
*s = '\0';
if (rve != NULL)
*rve = s;
return (s0);
}
#else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
char *
__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
}
#endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */