109 lines
3.2 KiB
C
109 lines
3.2 KiB
C
/*-
|
|
* Copyright (c) 2003 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 <inttypes.h>
|
|
#include <limits.h>
|
|
#include <math.h>
|
|
#include <stdlib.h>
|
|
#include "../stdio/floatio.h"
|
|
#include "fpmath.h"
|
|
#include "gdtoaimp.h"
|
|
|
|
/*
|
|
* ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
|
|
* except that the floating point argument is passed by reference.
|
|
* When dtoa() is passed a NaN or infinity, it sets expt to 9999.
|
|
* However, a long double could have a valid exponent of 9999, so we
|
|
* use INT_MAX in ldtoa() instead.
|
|
*/
|
|
char *
|
|
__ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign,
|
|
char **rve)
|
|
{
|
|
FPI fpi = {
|
|
LDBL_MANT_DIG, /* nbits */
|
|
LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */
|
|
LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */
|
|
FLT_ROUNDS, /* rounding */
|
|
#ifdef Sudden_Underflow /* unused, but correct anyway */
|
|
1
|
|
#else
|
|
0
|
|
#endif
|
|
};
|
|
int be, kind;
|
|
char *ret;
|
|
union IEEEl2bits u;
|
|
uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
|
|
void *vbits = bits;
|
|
|
|
u.e = *ld;
|
|
|
|
/*
|
|
* gdtoa doesn't know anything about the sign of the number, so
|
|
* if the number is negative, we need to swap rounding modes of
|
|
* 2 (upwards) and 3 (downwards).
|
|
*/
|
|
*sign = u.bits.sign;
|
|
fpi.rounding ^= (fpi.rounding >> 1) & u.bits.sign;
|
|
|
|
be = u.bits.exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1);
|
|
LDBL_TO_ARRAY32(u, bits);
|
|
|
|
switch (fpclassify(u.e)) {
|
|
case FP_NORMAL:
|
|
kind = STRTOG_Normal;
|
|
#ifdef LDBL_IMPLICIT_NBIT
|
|
bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
|
|
#endif /* LDBL_IMPLICIT_NBIT */
|
|
break;
|
|
case FP_ZERO:
|
|
kind = STRTOG_Zero;
|
|
break;
|
|
case FP_SUBNORMAL:
|
|
kind = STRTOG_Denormal;
|
|
be++;
|
|
break;
|
|
case FP_INFINITE:
|
|
kind = STRTOG_Infinite;
|
|
break;
|
|
case FP_NAN:
|
|
kind = STRTOG_NaN;
|
|
break;
|
|
default:
|
|
abort();
|
|
}
|
|
|
|
ret = gdtoa(&fpi, be, vbits, &kind, mode, ndigits, decpt, rve);
|
|
if (*decpt == -32768)
|
|
*decpt = INT_MAX;
|
|
return ret;
|
|
}
|