GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/gdtoa/hdtoa.c Lines: 0 97 0.0 %
Date: 2017-11-13 Branches: 0 80 0.0 %

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/*	$OpenBSD: hdtoa.c,v 1.3 2015/09/14 12:49:33 guenther Exp $	*/
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/*-
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 * Copyright (c) 2004, 2005 David Schultz <das@FreeBSD.ORG>
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/types.h>
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#include <machine/ieee.h>
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#include <float.h>
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#include <limits.h>
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#include <math.h>
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#include "gdtoaimp.h"
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/* Strings values used by dtoa() */
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#define	INFSTR	"Infinity"
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#define	NANSTR	"NaN"
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#define	DBL_ADJ		(DBL_MAX_EXP - 2 + ((DBL_MANT_DIG - 1) % 4))
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#define	LDBL_ADJ	(LDBL_MAX_EXP - 2 + ((LDBL_MANT_DIG - 1) % 4))
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/*
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 * Round up the given digit string.  If the digit string is fff...f,
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 * this procedure sets it to 100...0 and returns 1 to indicate that
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 * the exponent needs to be bumped.  Otherwise, 0 is returned.
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 */
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static int
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roundup(char *s0, int ndigits)
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{
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	char *s;
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	for (s = s0 + ndigits - 1; *s == 0xf; s--) {
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		if (s == s0) {
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			*s = 1;
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			return (1);
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		}
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		*s = 0;
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	}
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	++*s;
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	return (0);
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}
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/*
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 * Round the given digit string to ndigits digits according to the
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 * current rounding mode.  Note that this could produce a string whose
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 * value is not representable in the corresponding floating-point
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 * type.  The exponent pointed to by decpt is adjusted if necessary.
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 */
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static void
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dorounding(char *s0, int ndigits, int sign, int *decpt)
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{
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	int adjust = 0;	/* do we need to adjust the exponent? */
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	switch (FLT_ROUNDS) {
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	case 0:		/* toward zero */
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	default:	/* implementation-defined */
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		break;
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	case 1:		/* to nearest, halfway rounds to even */
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		if ((s0[ndigits] > 8) ||
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		    (s0[ndigits] == 8 && s0[ndigits + 1] & 1))
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			adjust = roundup(s0, ndigits);
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		break;
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	case 2:		/* toward +inf */
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		if (sign == 0)
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			adjust = roundup(s0, ndigits);
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		break;
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	case 3:		/* toward -inf */
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		if (sign != 0)
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			adjust = roundup(s0, ndigits);
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		break;
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	}
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	if (adjust)
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		*decpt += 4;
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}
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/*
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 * This procedure converts a double-precision number in IEEE format
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 * into a string of hexadecimal digits and an exponent of 2.  Its
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 * behavior is bug-for-bug compatible with dtoa() in mode 2, with the
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 * following exceptions:
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 *
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 * - An ndigits < 0 causes it to use as many digits as necessary to
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 *   represent the number exactly.
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 * - The additional xdigs argument should point to either the string
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 *   "0123456789ABCDEF" or the string "0123456789abcdef", depending on
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 *   which case is desired.
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 * - This routine does not repeat dtoa's mistake of setting decpt
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 *   to 9999 in the case of an infinity or NaN.  INT_MAX is used
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 *   for this purpose instead.
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 *
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 * Note that the C99 standard does not specify what the leading digit
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 * should be for non-zero numbers.  For instance, 0x1.3p3 is the same
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 * as 0x2.6p2 is the same as 0x4.cp3.  This implementation chooses the
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 * first digit so that subsequent digits are aligned on nibble
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 * boundaries (before rounding).
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 *
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 * Inputs:	d, xdigs, ndigits
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 * Outputs:	decpt, sign, rve
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 */
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char *
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__hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign,
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    char **rve)
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{
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	static const int sigfigs = (DBL_MANT_DIG + 3) / 4;
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	struct ieee_double *p = (struct ieee_double *)&d;
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	char *s, *s0;
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	int bufsize;
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	*sign = p->dbl_sign;
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	switch (fpclassify(d)) {
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	case FP_NORMAL:
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		*decpt = p->dbl_exp - DBL_ADJ;
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		break;
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	case FP_ZERO:
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		*decpt = 1;
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		return (nrv_alloc("0", rve, 1));
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	case FP_SUBNORMAL:
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		d *= 0x1p514;
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		*decpt = p->dbl_exp - (514 + DBL_ADJ);
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		break;
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	case FP_INFINITE:
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		*decpt = INT_MAX;
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		return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
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	case FP_NAN:
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		*decpt = INT_MAX;
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		return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
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	default:
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		abort();
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	}
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	/* FP_NORMAL or FP_SUBNORMAL */
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	if (ndigits == 0)		/* dtoa() compatibility */
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		ndigits = 1;
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	/*
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	 * For simplicity, we generate all the digits even if the
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	 * caller has requested fewer.
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	 */
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	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
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	s0 = rv_alloc(bufsize);
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	if (s0 == NULL)
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		return (NULL);
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	/*
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	 * We work from right to left, first adding any requested zero
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	 * padding, then the least significant portion of the
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	 * mantissa, followed by the most significant.  The buffer is
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	 * filled with the byte values 0x0 through 0xf, which are
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	 * converted to xdigs[0x0] through xdigs[0xf] after the
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	 * rounding phase.
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	 */
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	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
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		*s = 0;
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	for (; s > s0 + sigfigs - (DBL_FRACLBITS / 4) - 1 && s > s0; s--) {
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		*s = p->dbl_fracl & 0xf;
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		p->dbl_fracl >>= 4;
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	}
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	for (; s > s0; s--) {
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		*s = p->dbl_frach & 0xf;
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		p->dbl_frach >>= 4;
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	}
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	/*
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	 * At this point, we have snarfed all the bits in the
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	 * mantissa, with the possible exception of the highest-order
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	 * (partial) nibble, which is dealt with by the next
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	 * statement.  We also tack on the implicit normalization bit.
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	 */
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	*s = p->dbl_frach | (1U << ((DBL_MANT_DIG - 1) % 4));
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	/* If ndigits < 0, we are expected to auto-size the precision. */
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	if (ndigits < 0) {
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		for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
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			;
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	}
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	if (sigfigs > ndigits && s0[ndigits] != 0)
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		dorounding(s0, ndigits, p->dbl_sign, decpt);
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	s = s0 + ndigits;
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	if (rve != NULL)
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		*rve = s;
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	*s-- = '\0';
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	for (; s >= s0; s--)
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		*s = xdigs[(unsigned int)*s];
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	return (s0);
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}
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DEF_STRONG(__hdtoa);
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#if (LDBL_MANT_DIG > DBL_MANT_DIG)
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/*
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 * This is the long double version of __hdtoa().
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 */
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char *
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__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
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    char **rve)
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{
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	static const int sigfigs = (LDBL_MANT_DIG + 3) / 4;
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	struct ieee_ext *p = (struct ieee_ext *)&e;
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	char *s, *s0;
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	int bufsize;
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	*sign = p->ext_sign;
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	switch (fpclassify(e)) {
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	case FP_NORMAL:
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		*decpt = p->ext_exp - LDBL_ADJ;
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		break;
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	case FP_ZERO:
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		*decpt = 1;
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		return (nrv_alloc("0", rve, 1));
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	case FP_SUBNORMAL:
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		e *= 0x1p514L;
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		*decpt = p->ext_exp - (514 + LDBL_ADJ);
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		break;
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	case FP_INFINITE:
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		*decpt = INT_MAX;
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		return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
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	case FP_NAN:
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		*decpt = INT_MAX;
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		return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
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	default:
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		abort();
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	}
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	/* FP_NORMAL or FP_SUBNORMAL */
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	if (ndigits == 0)		/* dtoa() compatibility */
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		ndigits = 1;
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	/*
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	 * For simplicity, we generate all the digits even if the
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	 * caller has requested fewer.
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	 */
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	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
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	s0 = rv_alloc(bufsize);
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	if (s0 == NULL)
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		return (NULL);
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	/*
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	 * We work from right to left, first adding any requested zero
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	 * padding, then the least significant portion of the
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	 * mantissa, followed by the most significant.  The buffer is
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	 * filled with the byte values 0x0 through 0xf, which are
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	 * converted to xdigs[0x0] through xdigs[0xf] after the
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	 * rounding phase.
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	 */
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	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
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		*s = 0;
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	for (; s > s0 + sigfigs - (EXT_FRACLBITS / 4) - 1 && s > s0; s--) {
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		*s = p->ext_fracl & 0xf;
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		p->ext_fracl >>= 4;
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	}
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#ifdef EXT_FRACHMBITS
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	for (; s > s0; s--) {
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		*s = p->ext_frachm & 0xf;
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		p->ext_frachm >>= 4;
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	}
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#endif
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#ifdef EXT_FRACLMBITS
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	for (; s > s0; s--) {
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		*s = p->ext_fraclm & 0xf;
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		p->ext_fraclm >>= 4;
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	}
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#endif
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	for (; s > s0; s--) {
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		*s = p->ext_frach & 0xf;
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		p->ext_frach >>= 4;
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	}
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	/*
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	 * At this point, we have snarfed all the bits in the
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	 * mantissa, with the possible exception of the highest-order
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	 * (partial) nibble, which is dealt with by the next
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	 * statement.  We also tack on the implicit normalization bit.
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	 */
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	*s = p->ext_frach | (1U << ((LDBL_MANT_DIG - 1) % 4));
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	/* If ndigits < 0, we are expected to auto-size the precision. */
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	if (ndigits < 0) {
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		for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
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			;
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	}
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	if (sigfigs > ndigits && s0[ndigits] != 0)
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		dorounding(s0, ndigits, p->ext_sign, decpt);
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	s = s0 + ndigits;
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	if (rve != NULL)
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		*rve = s;
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	*s-- = '\0';
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	for (; s >= s0; s--)
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		*s = xdigs[(unsigned int)*s];
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	return (s0);
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}
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DEF_STRONG(__hldtoa);
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#else	/* (LDBL_MANT_DIG == DBL_MANT_DIG) */
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char *
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__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
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    char **rve)
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{
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	return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
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}
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DEF_STRONG(__hldtoa);
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#endif	/* (LDBL_MANT_DIG == DBL_MANT_DIG) */