[mirror_ubuntu-artful-kernel.git] / arch / mips / math-emu / dp_div.c

/* IEEE754 floating point arithmetic
 * double precision: common utilities
 */
/*
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.
 *
 * ########################################################################
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 */


#include "ieee754dp.h"

union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y)
{
	COMPXDP;
	COMPYDP;

	EXPLODEXDP;
	EXPLODEYDP;

	ieee754_clearcx();

	FLUSHXDP;
	FLUSHYDP;

	switch (CLPAIR(xc, yc)) {
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754dp_nanxcpt(ieee754dp_indef());

	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
		return y;

	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
		return x;


		/* Infinity handling
		 */

	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754dp_indef();

	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
		return ieee754dp_zero(xs ^ ys);

	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
		return ieee754dp_inf(xs ^ ys);

		/* Zero handling
		 */

	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754dp_indef();

	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
		ieee754_setcx(IEEE754_ZERO_DIVIDE);
		return ieee754dp_inf(xs ^ ys);

	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
		return ieee754dp_zero(xs == ys ? 0 : 1);

	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
		DPDNORMX;

	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
		DPDNORMY;
		break;

	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
		DPDNORMX;
		break;

	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
		break;
	}
	assert(xm & DP_HIDDEN_BIT);
	assert(ym & DP_HIDDEN_BIT);

	/* provide rounding space */
	xm <<= 3;
	ym <<= 3;

	{
		/* now the dirty work */

		u64 rm = 0;
		int re = xe - ye;
		u64 bm;

		for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) {
			if (xm >= ym) {
				xm -= ym;
				rm |= bm;
				if (xm == 0)
					break;
			}
			xm <<= 1;
		}
		rm <<= 1;
		if (xm)
			rm |= 1;	/* have remainder, set sticky */

		assert(rm);

		/* normalise rm to rounding precision ?
		 */
		while ((rm >> (DP_FBITS + 3)) == 0) {
			rm <<= 1;
			re--;
		}

		return ieee754dp_format(xs == ys ? 0 : 1, re, rm);
	}
}
Commit	Line	Data
1da177e4 LT	1	/* IEEE754 floating point arithmetic
	2	* double precision: common utilities
	3	*/
	4	/*
	5	* MIPS floating point support
	6	* Copyright (C) 1994-2000 Algorithmics Ltd.
1da177e4 LT	7	*
	8	* ########################################################################
	9	*
	10	* This program is free software; you can distribute it and/or modify it
	11	* under the terms of the GNU General Public License (Version 2) as
	12	* published by the Free Software Foundation.
	13	*
	14	* This program is distributed in the hope it will be useful, but WITHOUT
	15	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	16	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	17	* for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License along
	20	* with this program; if not, write to the Free Software Foundation, Inc.,
	21	* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
	22	*
	23	* ########################################################################
	24	*/
	25
	26
	27	#include "ieee754dp.h"
	28
2209bcb1	29	union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y)
1da177e4 LT	30	{
	31	COMPXDP;
	32	COMPYDP;
	33
	34	EXPLODEXDP;
	35	EXPLODEYDP;
	36
9e8bad1f	37	ieee754_clearcx();
1da177e4 LT	38
	39	FLUSHXDP;
	40	FLUSHYDP;
	41
	42	switch (CLPAIR(xc, yc)) {
	43	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
	44	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
	45	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
	46	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
	47	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
	48	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
	49	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
	50	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
	51	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
	52	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
	53	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
9e8bad1f	54	ieee754_setcx(IEEE754_INVALID_OPERATION);
90efba36	55	return ieee754dp_nanxcpt(ieee754dp_indef());
1da177e4 LT	56
	57	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
	58	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
	59	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
	60	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
	61	return y;
	62
	63	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
	64	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
	65	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
	66	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
	67	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
	68	return x;
	69
	70
	71	/* Infinity handling
	72	*/
	73
	74	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
9e8bad1f	75	ieee754_setcx(IEEE754_INVALID_OPERATION);
90efba36	76	return ieee754dp_indef();
1da177e4 LT	77
	78	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
	79	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
	80	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
	81	return ieee754dp_zero(xs ^ ys);
	82
	83	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
	84	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
	85	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
	86	return ieee754dp_inf(xs ^ ys);
	87
	88	/* Zero handling
	89	*/
	90
	91	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
9e8bad1f	92	ieee754_setcx(IEEE754_INVALID_OPERATION);
90efba36	93	return ieee754dp_indef();
1da177e4 LT	94
	95	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
	96	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
9e8bad1f	97	ieee754_setcx(IEEE754_ZERO_DIVIDE);
90efba36	98	return ieee754dp_inf(xs ^ ys);
1da177e4 LT	99
	100	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
	101	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
	102	return ieee754dp_zero(xs == ys ? 0 : 1);
	103
	104	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
	105	DPDNORMX;
	106
	107	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
	108	DPDNORMY;
	109	break;
	110
	111	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
	112	DPDNORMX;
	113	break;
	114
	115	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
	116	break;
	117	}
	118	assert(xm & DP_HIDDEN_BIT);
	119	assert(ym & DP_HIDDEN_BIT);
	120
	121	/* provide rounding space */
	122	xm <<= 3;
	123	ym <<= 3;
	124
	125	{
	126	/* now the dirty work */
	127
	128	u64 rm = 0;
	129	int re = xe - ye;
	130	u64 bm;
	131
ad8fb553	132	for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) {
1da177e4 LT	133	if (xm >= ym) {
	134	xm -= ym;
	135	rm \|= bm;
	136	if (xm == 0)
	137	break;
	138	}
	139	xm <<= 1;
	140	}
	141	rm <<= 1;
	142	if (xm)
	143	rm \|= 1; /* have remainder, set sticky */
	144
	145	assert(rm);
	146
	147	/* normalise rm to rounding precision ?
	148	*/
ad8fb553	149	while ((rm >> (DP_FBITS + 3)) == 0) {
1da177e4 LT	150	rm <<= 1;
	151	re--;
	152	}
	153
90efba36	154	return ieee754dp_format(xs == ys ? 0 : 1, re, rm);
1da177e4 LT	155	}
1da177e4 LT	156	}