[apple/libc.git] / gdtoa / FreeBSD / _hdtoa.c

/*-
 * Copyright (c) 2004, 2005 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: src/lib/libc/gdtoa/_hdtoa.c,v 1.5 2007/05/08 02:59:37 das Exp $");

#include <float.h>
#include <limits.h>
#include <math.h>
#include "fpmath.h"
#include "gdtoaimp.h"

/* Strings values used by dtoa() */
#define	INFSTR	"Infinity"
#define	NANSTR	"NaN"

#define	DBL_ADJ		(DBL_MAX_EXP - 2 + ((DBL_MANT_DIG - 1) % 4))
#define	LDBL_ADJ	(LDBL_MAX_EXP - 2 + ((LDBL_MANT_DIG - 1) % 4))

/*
 * Round up the given digit string.  If the digit string is fff...f,
 * this procedure sets it to 100...0 and returns 1 to indicate that
 * the exponent needs to be bumped.  Otherwise, 0 is returned.
 */
static int
roundup(char *s0, int ndigits)
{
	char *s;

	for (s = s0 + ndigits - 1; *s == 0xf; s--) {
		if (s == s0) {
			*s = 1;
			return (1);
		}
		*s = 0;
	}
	++*s;
	return (0);
}

/*
 * Round the given digit string to ndigits digits according to the
 * current rounding mode.  Note that this could produce a string whose
 * value is not representable in the corresponding floating-point
 * type.  The exponent pointed to by decpt is adjusted if necessary.
 */
static void
dorounding(char *s0, int ndigits, int sign, int *decpt)
{
	int adjust = 0;	/* do we need to adjust the exponent? */

	switch (FLT_ROUNDS) {
	case 0:		/* toward zero */
	default:	/* implementation-defined */
		break;
	case 1:		/* to nearest, halfway rounds to even */
		if ((s0[ndigits] > 8) ||
		    (s0[ndigits] == 8 && s0[ndigits + 1] & 1))
			adjust = roundup(s0, ndigits);
		break;
	case 2:		/* toward +inf */
		if (sign == 0)
			adjust = roundup(s0, ndigits);
		break;
	case 3:		/* toward -inf */
		if (sign != 0)
			adjust = roundup(s0, ndigits);
		break;
	}

	if (adjust)
		*decpt += 4;
}

/*
 * This procedure converts a double-precision number in IEEE format
 * into a string of hexadecimal digits and an exponent of 2.  Its
 * behavior is bug-for-bug compatible with dtoa() in mode 2, with the
 * following exceptions:
 *
 * - An ndigits < 0 causes it to use as many digits as necessary to
 *   represent the number exactly.
 * - The additional xdigs argument should point to either the string
 *   "0123456789ABCDEF" or the string "0123456789abcdef", depending on
 *   which case is desired.
 * - This routine does not repeat dtoa's mistake of setting decpt
 *   to 9999 in the case of an infinity or NaN.  INT_MAX is used
 *   for this purpose instead.
 *
 * Note that the C99 standard does not specify what the leading digit
 * should be for non-zero numbers.  For instance, 0x1.3p3 is the same
 * as 0x2.6p2 is the same as 0x4.cp3.  This implementation chooses the
 * first digit so that subsequent digits are aligned on nibble
 * boundaries (before rounding).
 *
 * Inputs:	d, xdigs, ndigits
 * Outputs:	decpt, sign, rve
 */
char *
__hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign,
    char **rve)
{
	static const int sigfigs = (DBL_MANT_DIG + 3) / 4;
	union IEEEd2bits u;
	char *s, *s0;
	int bufsize, f;

	u.d = d;
	*sign = u.bits.sign;

	switch (f = fpclassify(d)) {
	case FP_NORMAL:
		*decpt = u.bits.exp - DBL_ADJ;
		break;
	case FP_ZERO:
return_zero:
		*decpt = 1;
		return (nrv_alloc("0", rve, 1));
	case FP_SUBNORMAL:
		/*
		 * For processors that treat subnormals as zero, comparison
		 * with zero will be equal, so we jump to the FP_ZERO case.
		 */
		if(u.d == 0.0) goto return_zero;
		u.d *= 0x1p514;
		*decpt = u.bits.exp - (514 + DBL_ADJ);
		break;
	case FP_INFINITE:
		*decpt = INT_MAX;
		return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
	case FP_NAN:
		*decpt = INT_MAX;
		return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
	default:
		LIBC_ABORT("fpclassify returned %d", f);
	}

	/* FP_NORMAL or FP_SUBNORMAL */

	if (ndigits == 0)		/* dtoa() compatibility */
		ndigits = 1;

	/*
	 * For simplicity, we generate all the digits even if the
	 * caller has requested fewer.
	 */
	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
	s0 = rv_alloc(bufsize);

	/*
	 * We work from right to left, first adding any requested zero
	 * padding, then the least significant portion of the
	 * mantissa, followed by the most significant.  The buffer is
	 * filled with the byte values 0x0 through 0xf, which are
	 * converted to xdigs[0x0] through xdigs[0xf] after the
	 * rounding phase.
	 */
	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
		*s = 0;
	for (; s > s0 + sigfigs - (DBL_MANL_SIZE / 4) - 1 && s > s0; s--) {
		*s = u.bits.manl & 0xf;
		u.bits.manl >>= 4;
	}
	for (; s > s0; s--) {
		*s = u.bits.manh & 0xf;
		u.bits.manh >>= 4;
	}

	/*
	 * At this point, we have snarfed all the bits in the
	 * mantissa, with the possible exception of the highest-order
	 * (partial) nibble, which is dealt with by the next
	 * statement.  We also tack on the implicit normalization bit.
	 */
	*s = u.bits.manh | (1U << ((DBL_MANT_DIG - 1) % 4));

	/* If ndigits < 0, we are expected to auto-size the precision. */
	if (ndigits < 0) {
		for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
			;
	}

	if (sigfigs > ndigits && s0[ndigits] != 0)
		dorounding(s0, ndigits, u.bits.sign, decpt);

	s = s0 + ndigits;
	if (rve != NULL)
		*rve = s;
	*s-- = '\0';
	for (; s >= s0; s--)
		*s = xdigs[(unsigned int)*s];

	return (s0);
}

#if (LDBL_MANT_DIG > DBL_MANT_DIG)

/*
 * This is the long double version of __hdtoa().
 */
char *
__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
    char **rve)
{
	static const int sigfigs = (LDBL_MANT_DIG + 3) / 4;
	union IEEEl2bits u;
	char *s, *s0;
	int bufsize, f;

	u.e = e;
	*sign = u.bits.sign;

	switch (f = fpclassify(e)) {
	case FP_NORMAL:
	case FP_SUPERNORMAL:
		*decpt = u.bits.exp - LDBL_ADJ;
		break;
	case FP_ZERO:
		*decpt = 1;
		return (nrv_alloc("0", rve, 1));
	case FP_SUBNORMAL:
		u.e *= 0x1p514L;
		*decpt = u.bits.exp - (514 + LDBL_ADJ);
		break;
	case FP_INFINITE:
		*decpt = INT_MAX;
		return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
	case FP_NAN:
		*decpt = INT_MAX;
		return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
	default:
		LIBC_ABORT("fpclassify returned %d", f);
	}

	/* FP_NORMAL or FP_SUBNORMAL */

	if (ndigits == 0)		/* dtoa() compatibility */
		ndigits = 1;

	/*
	 * For simplicity, we generate all the digits even if the
	 * caller has requested fewer.
	 */
	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
	s0 = rv_alloc(bufsize);

	/*
	 * We work from right to left, first adding any requested zero
	 * padding, then the least significant portion of the
	 * mantissa, followed by the most significant.  The buffer is
	 * filled with the byte values 0x0 through 0xf, which are
	 * converted to xdigs[0x0] through xdigs[0xf] after the
	 * rounding phase.
	 */
	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
		*s = 0;
	for (; s > s0 + sigfigs - (LDBL_MANL_SIZE / 4) - 1 && s > s0; s--) {
		*s = u.bits.manl & 0xf;
		u.bits.manl >>= 4;
	}
	for (; s > s0; s--) {
		*s = u.bits.manh & 0xf;
		u.bits.manh >>= 4;
	}

	/*
	 * At this point, we have snarfed all the bits in the
	 * mantissa, with the possible exception of the highest-order
	 * (partial) nibble, which is dealt with by the next
	 * statement.  We also tack on the implicit normalization bit.
	 */
	*s = u.bits.manh | (1U << ((LDBL_MANT_DIG - 1) % 4));

	/* If ndigits < 0, we are expected to auto-size the precision. */
	if (ndigits < 0) {
		for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
			;
	}

	if (sigfigs > ndigits && s0[ndigits] != 0)
		dorounding(s0, ndigits, u.bits.sign, decpt);

	s = s0 + ndigits;
	if (rve != NULL)
		*rve = s;
	*s-- = '\0';
	for (; s >= s0; s--)
		*s = xdigs[(unsigned int)*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) */
Commit	Line	Data
59e0d9fe	1	/*-
31185420	2	* Copyright (c) 2004, 2005 David Schultz <das@FreeBSD.ORG>
59e0d9fe A	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	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.
	13	*
	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
	24	* SUCH DAMAGE.
	25	*/
	26
	27	#include <sys/cdefs.h>
ad3c9f2a	28	__FBSDID("$FreeBSD: src/lib/libc/gdtoa/_hdtoa.c,v 1.5 2007/05/08 02:59:37 das Exp $");
59e0d9fe A	29
59e0d9fe A	30	#include <float.h>
59e0d9fe A	31	#include <limits.h>
59e0d9fe A	32	#include <math.h>
59e0d9fe A	33	#include "fpmath.h"
	34	#include "gdtoaimp.h"
	35
	36	/* Strings values used by dtoa() */
	37	#define INFSTR "Infinity"
	38	#define NANSTR "NaN"
	39
31185420 A	40	#define DBL_ADJ (DBL_MAX_EXP - 2 + ((DBL_MANT_DIG - 1) % 4))
31185420 A	41	#define LDBL_ADJ (LDBL_MAX_EXP - 2 + ((LDBL_MANT_DIG - 1) % 4))
59e0d9fe A	42
	43	/*
	44	* Round up the given digit string. If the digit string is fff...f,
	45	* this procedure sets it to 100...0 and returns 1 to indicate that
	46	* the exponent needs to be bumped. Otherwise, 0 is returned.
	47	*/
	48	static int
	49	roundup(char *s0, int ndigits)
	50	{
	51	char *s;
	52
	53	for (s = s0 + ndigits - 1; *s == 0xf; s--) {
	54	if (s == s0) {
	55	*s = 1;
	56	return (1);
	57	}
ad3c9f2a	58	*s = 0;
59e0d9fe A	59	}
	60	++*s;
	61	return (0);
	62	}
	63
	64	/*
	65	* Round the given digit string to ndigits digits according to the
	66	* current rounding mode. Note that this could produce a string whose
	67	* value is not representable in the corresponding floating-point
	68	* type. The exponent pointed to by decpt is adjusted if necessary.
	69	*/
	70	static void
	71	dorounding(char s0, int ndigits, int sign, int decpt)
	72	{
	73	int adjust = 0; /* do we need to adjust the exponent? */
	74
	75	switch (FLT_ROUNDS) {
	76	case 0: /* toward zero */
	77	default: /* implementation-defined */
	78	break;
	79	case 1: /* to nearest, halfway rounds to even */
	80	if ((s0[ndigits] > 8) \|\|
ad3c9f2a	81	(s0[ndigits] == 8 && s0[ndigits + 1] & 1))
59e0d9fe A	82	adjust = roundup(s0, ndigits);
	83	break;
	84	case 2: /* toward +inf */
	85	if (sign == 0)
	86	adjust = roundup(s0, ndigits);
	87	break;
	88	case 3: /* toward -inf */
	89	if (sign != 0)
	90	adjust = roundup(s0, ndigits);
	91	break;
	92	}
	93
	94	if (adjust)
	95	*decpt += 4;
	96	}
	97
	98	/*
	99	* This procedure converts a double-precision number in IEEE format
	100	* into a string of hexadecimal digits and an exponent of 2. Its
	101	* behavior is bug-for-bug compatible with dtoa() in mode 2, with the
	102	* following exceptions:
	103	*
	104	* - An ndigits < 0 causes it to use as many digits as necessary to
	105	* represent the number exactly.
	106	* - The additional xdigs argument should point to either the string
	107	* "0123456789ABCDEF" or the string "0123456789abcdef", depending on
	108	* which case is desired.
	109	* - This routine does not repeat dtoa's mistake of setting decpt
	110	* to 9999 in the case of an infinity or NaN. INT_MAX is used
	111	* for this purpose instead.
	112	*
	113	* Note that the C99 standard does not specify what the leading digit
	114	* should be for non-zero numbers. For instance, 0x1.3p3 is the same
	115	* as 0x2.6p2 is the same as 0x4.cp3. This implementation chooses the
	116	* first digit so that subsequent digits are aligned on nibble
	117	* boundaries (before rounding).
	118	*
	119	* Inputs: d, xdigs, ndigits
	120	* Outputs: decpt, sign, rve
	121	*/
	122	char *
	123	__hdtoa(double d, const char xdigs, int ndigits, int decpt, int *sign,
	124	char **rve)
	125	{
31185420	126	static const int sigfigs = (DBL_MANT_DIG + 3) / 4;
59e0d9fe A	127	union IEEEd2bits u;
59e0d9fe A	128	char s, s0;
ad3c9f2a	129	int bufsize, f;
59e0d9fe A	130
	131	u.d = d;
	132	*sign = u.bits.sign;
	133
ad3c9f2a	134	switch (f = fpclassify(d)) {
59e0d9fe	135	case FP_NORMAL:
31185420	136	*decpt = u.bits.exp - DBL_ADJ;
59e0d9fe A	137	break;
59e0d9fe A	138	case FP_ZERO:
ad3c9f2a	139	return_zero:
59e0d9fe A	140	*decpt = 1;
	141	return (nrv_alloc("0", rve, 1));
	142	case FP_SUBNORMAL:
ad3c9f2a A	143	/*
	144	* For processors that treat subnormals as zero, comparison
	145	* with zero will be equal, so we jump to the FP_ZERO case.
	146	*/
	147	if(u.d == 0.0) goto return_zero;
31185420 A	148	u.d *= 0x1p514;
31185420 A	149	*decpt = u.bits.exp - (514 + DBL_ADJ);
59e0d9fe A	150	break;
	151	case FP_INFINITE:
	152	*decpt = INT_MAX;
	153	return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
	154	case FP_NAN:
	155	*decpt = INT_MAX;
	156	return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
	157	default:
ad3c9f2a	158	LIBC_ABORT("fpclassify returned %d", f);
59e0d9fe A	159	}
	160
	161	/* FP_NORMAL or FP_SUBNORMAL */
	162
	163	if (ndigits == 0) /* dtoa() compatibility */
	164	ndigits = 1;
	165
	166	/*
	167	* For simplicity, we generate all the digits even if the
	168	* caller has requested fewer.
	169	*/
	170	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
	171	s0 = rv_alloc(bufsize);
	172
	173	/*
	174	* We work from right to left, first adding any requested zero
	175	* padding, then the least significant portion of the
	176	* mantissa, followed by the most significant. The buffer is
	177	* filled with the byte values 0x0 through 0xf, which are
	178	* converted to xdigs[0x0] through xdigs[0xf] after the
	179	* rounding phase.
	180	*/
	181	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
	182	*s = 0;
	183	for (; s > s0 + sigfigs - (DBL_MANL_SIZE / 4) - 1 && s > s0; s--) {
	184	*s = u.bits.manl & 0xf;
	185	u.bits.manl >>= 4;
	186	}
	187	for (; s > s0; s--) {
	188	*s = u.bits.manh & 0xf;
	189	u.bits.manh >>= 4;
	190	}
	191
	192	/*
	193	* At this point, we have snarfed all the bits in the
	194	* mantissa, with the possible exception of the highest-order
	195	* (partial) nibble, which is dealt with by the next
31185420	196	* statement. We also tack on the implicit normalization bit.
59e0d9fe	197	*/
31185420	198	*s = u.bits.manh \| (1U << ((DBL_MANT_DIG - 1) % 4));
59e0d9fe A	199
	200	/* If ndigits < 0, we are expected to auto-size the precision. */
	201	if (ndigits < 0) {
	202	for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
	203	;
	204	}
	205
	206	if (sigfigs > ndigits && s0[ndigits] != 0)
	207	dorounding(s0, ndigits, u.bits.sign, decpt);
	208
	209	s = s0 + ndigits;
	210	if (rve != NULL)
	211	*rve = s;
	212	*s-- = '\0';
	213	for (; s >= s0; s--)
	214	s = xdigs[(unsigned int)s];
	215
	216	return (s0);
	217	}
	218
	219	#if (LDBL_MANT_DIG > DBL_MANT_DIG)
	220
	221	/*
	222	* This is the long double version of __hdtoa().
59e0d9fe A	223	*/
	224	char *
	225	__hldtoa(long double e, const char xdigs, int ndigits, int decpt, int *sign,
	226	char **rve)
	227	{
31185420	228	static const int sigfigs = (LDBL_MANT_DIG + 3) / 4;
59e0d9fe A	229	union IEEEl2bits u;
59e0d9fe A	230	char s, s0;
ad3c9f2a	231	int bufsize, f;
59e0d9fe A	232
	233	u.e = e;
	234	*sign = u.bits.sign;
	235
ad3c9f2a	236	switch (f = fpclassify(e)) {
59e0d9fe	237	case FP_NORMAL:
ad3c9f2a	238	case FP_SUPERNORMAL:
31185420	239	*decpt = u.bits.exp - LDBL_ADJ;
59e0d9fe A	240	break;
	241	case FP_ZERO:
	242	*decpt = 1;
	243	return (nrv_alloc("0", rve, 1));
	244	case FP_SUBNORMAL:
31185420 A	245	u.e *= 0x1p514L;
31185420 A	246	*decpt = u.bits.exp - (514 + LDBL_ADJ);
59e0d9fe A	247	break;
	248	case FP_INFINITE:
	249	*decpt = INT_MAX;
	250	return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
	251	case FP_NAN:
	252	*decpt = INT_MAX;
	253	return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
	254	default:
ad3c9f2a	255	LIBC_ABORT("fpclassify returned %d", f);
59e0d9fe A	256	}
	257
	258	/* FP_NORMAL or FP_SUBNORMAL */
	259
	260	if (ndigits == 0) /* dtoa() compatibility */
	261	ndigits = 1;
	262
	263	/*
	264	* For simplicity, we generate all the digits even if the
	265	* caller has requested fewer.
	266	*/
	267	bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
	268	s0 = rv_alloc(bufsize);
	269
	270	/*
	271	* We work from right to left, first adding any requested zero
	272	* padding, then the least significant portion of the
	273	* mantissa, followed by the most significant. The buffer is
	274	* filled with the byte values 0x0 through 0xf, which are
	275	* converted to xdigs[0x0] through xdigs[0xf] after the
	276	* rounding phase.
	277	*/
	278	for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
	279	*s = 0;
	280	for (; s > s0 + sigfigs - (LDBL_MANL_SIZE / 4) - 1 && s > s0; s--) {
	281	*s = u.bits.manl & 0xf;
	282	u.bits.manl >>= 4;
	283	}
	284	for (; s > s0; s--) {
	285	*s = u.bits.manh & 0xf;
	286	u.bits.manh >>= 4;
	287	}
	288
	289	/*
	290	* At this point, we have snarfed all the bits in the
	291	* mantissa, with the possible exception of the highest-order
	292	* (partial) nibble, which is dealt with by the next
31185420	293	* statement. We also tack on the implicit normalization bit.
59e0d9fe	294	*/
31185420	295	*s = u.bits.manh \| (1U << ((LDBL_MANT_DIG - 1) % 4));
59e0d9fe A	296
	297	/* If ndigits < 0, we are expected to auto-size the precision. */
	298	if (ndigits < 0) {
	299	for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
	300	;
	301	}
	302
	303	if (sigfigs > ndigits && s0[ndigits] != 0)
	304	dorounding(s0, ndigits, u.bits.sign, decpt);
	305
	306	s = s0 + ndigits;
	307	if (rve != NULL)
	308	*rve = s;
	309	*s-- = '\0';
	310	for (; s >= s0; s--)
	311	s = xdigs[(unsigned int)s];
	312
	313	return (s0);
	314	}
	315
	316	#else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
	317
	318	char *
	319	__hldtoa(long double e, const char xdigs, int ndigits, int decpt, int *sign,
	320	char **rve)
	321	{
	322
	323	return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
	324	}
	325
	326	#endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */