[apple/libc.git] / gdtoa / _ldbl_util.c

/*
 * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http:www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

#include <sys/cdefs.h>
#include <stdint.h>
#include <strings.h>
#include <float.h>
#include <math.h>
#include <alloca.h>

#include "fpmath.h"

#define	BITS64		64
#define	DBL_BIAS	(DBL_MAX_EXP - 1)
#define	DBL_SUBEXP	(-DBL_BIAS + 1)
#define	LL_BITS		(8 * sizeof(int64_t))
#define	LL_HIGHBIT	(1LL << 63)

__private_extern__ void
_ldbl2array32dd(union IEEEl2bits u, uint32_t *a)
{
	int bit, shift, highbit, dexp;
	uint64_t a64[2];
	int64_t t64;

	bzero(a64, sizeof(a64));

	switch (__fpclassifyd(u.d[0])) {
	case FP_NORMAL:
		a64[1] = (1LL << (LDBL_MANT_DIG - BITS64 - 1));
		/* drop through */
	case FP_SUBNORMAL:
		a64[1] |= ((uint64_t)u.bits.manh >> (BITS64 - LDBL_MANL_SIZE));
		a64[0] = ((uint64_t)u.bits.manh << LDBL_MANL_SIZE);
		break;
	default:
		goto done;
	}

	dexp = (int)u.bits.exp - (int)u.bits.exp2;
	/*
	 * if the tail double is so small to not fit in LDBL_MANT_DIG bits,
	 * then just skip it.
	 */
	if (dexp >= LDBL_MANT_DIG)
		goto done;

	switch (__fpclassifyd(u.d[1])) {
	case FP_NORMAL:
		bit = LDBL_MANT_DIG - dexp - 1;
		t64 = (1LL << bit);
		break;
	case FP_SUBNORMAL:
		bit = LDBL_MANT_DIG - (int)u.bits.exp;
		t64 = 0;
		break;
	default:
		goto done;
	}
	shift = LDBL_MANL_SIZE - bit - 1;
	if (shift >= 0)
		t64 |= (u.bits.manl >> shift);
	else
		t64 |= (u.bits.manl << (-shift));
	highbit = ((a64[0] & LL_HIGHBIT) != 0);
	if (u.bits.sign == u.bits.sign2) {
		a64[0] += t64;
		if (highbit && !(a64[0] & LL_HIGHBIT))	/* carry */
			a64[1]++;
	} else {
		a64[0] -= t64;
		if (!highbit && (a64[0] & LL_HIGHBIT))	/* borrow */
			a64[1]--;
	}

	done:
	a[0] = (uint32_t)a64[0];
	a[1] = (uint32_t)(a64[0] >> 32);
	a[2] = (uint32_t)a64[1];
	a[3] = (uint32_t)(a64[1] >> 32);
}
Commit	Line	Data
3d9156a7 A	1	/*
	2	* Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. Please obtain a copy of the License at
	10	* http:www.opensource.apple.com/apsl/ and read it before using this
	11	* file.
	12	*
	13	* The Original Code and all software distributed under the License are
	14	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	15	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	16	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	17	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	* Please see the License for the specific language governing rights and
	19	* limitations under the License.
	20	*
	21	* @APPLE_LICENSE_HEADER_END@
	22	*/
	23
	24	#include <sys/cdefs.h>
	25	#include <stdint.h>
	26	#include <strings.h>
	27	#include <float.h>
	28	#include <math.h>
	29	#include <alloca.h>
	30
	31	#include "fpmath.h"
	32
	33	#define BITS64 64
	34	#define DBL_BIAS (DBL_MAX_EXP - 1)
	35	#define DBL_SUBEXP (-DBL_BIAS + 1)
	36	#define LL_BITS (8 * sizeof(int64_t))
	37	#define LL_HIGHBIT (1LL << 63)
	38
	39	__private_extern__ void
	40	_ldbl2array32dd(union IEEEl2bits u, uint32_t *a)
	41	{
224c7076	42	int bit, shift, highbit, dexp;
3d9156a7 A	43	uint64_t a64[2];
	44	int64_t t64;
	45
224c7076	46	bzero(a64, sizeof(a64));
3d9156a7 A	47
	48	switch (__fpclassifyd(u.d[0])) {
	49	case FP_NORMAL:
	50	a64[1] = (1LL << (LDBL_MANT_DIG - BITS64 - 1));
	51	/* drop through */
	52	case FP_SUBNORMAL:
	53	a64[1] \|= ((uint64_t)u.bits.manh >> (BITS64 - LDBL_MANL_SIZE));
	54	a64[0] = ((uint64_t)u.bits.manh << LDBL_MANL_SIZE);
	55	break;
	56	default:
	57	goto done;
	58	}
	59
224c7076 A	60	dexp = (int)u.bits.exp - (int)u.bits.exp2;
	61	/*
	62	* if the tail double is so small to not fit in LDBL_MANT_DIG bits,
	63	* then just skip it.
	64	*/
	65	if (dexp >= LDBL_MANT_DIG)
	66	goto done;
	67
3d9156a7 A	68	switch (__fpclassifyd(u.d[1])) {
3d9156a7 A	69	case FP_NORMAL:
224c7076	70	bit = LDBL_MANT_DIG - dexp - 1;
3d9156a7 A	71	t64 = (1LL << bit);
	72	break;
	73	case FP_SUBNORMAL:
	74	bit = LDBL_MANT_DIG - (int)u.bits.exp;
	75	t64 = 0;
	76	break;
	77	default:
	78	goto done;
	79	}
	80	shift = LDBL_MANL_SIZE - bit - 1;
	81	if (shift >= 0)
	82	t64 \|= (u.bits.manl >> shift);
	83	else
	84	t64 \|= (u.bits.manl << (-shift));
	85	highbit = ((a64[0] & LL_HIGHBIT) != 0);
	86	if (u.bits.sign == u.bits.sign2) {
	87	a64[0] += t64;
	88	if (highbit && !(a64[0] & LL_HIGHBIT)) /* carry */
	89	a64[1]++;
	90	} else {
	91	a64[0] -= t64;
	92	if (!highbit && (a64[0] & LL_HIGHBIT)) /* borrow */
	93	a64[1]--;
	94	}
	95
	96	done:
	97	a[0] = (uint32_t)a64[0];
	98	a[1] = (uint32_t)(a64[0] >> 32);
	99	a[2] = (uint32_t)a64[1];
	100	a[3] = (uint32_t)(a64[1] >> 32);
	101	}