[deliverable/linux.git] / arch / mips / math-emu / sp_tlong.c

/* IEEE754 floating point arithmetic
 * single precision
 */
/*
 * 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.,
 *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
 */

#include "ieee754sp.h"
#include "ieee754dp.h"

s64 ieee754sp_tlong(union ieee754sp x)
{
	u32 residue;
	int round;
	int sticky;
	int odd;

	COMPXDP;		/* <-- need 64-bit mantissa tmp */

	ieee754_clearcx();

	EXPLODEXSP;
	FLUSHXSP;

	switch (xc) {
	case IEEE754_CLASS_SNAN:
	case IEEE754_CLASS_QNAN:
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754di_indef();

	case IEEE754_CLASS_INF:
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754di_overflow(xs);

	case IEEE754_CLASS_ZERO:
		return 0;

	case IEEE754_CLASS_DNORM:
	case IEEE754_CLASS_NORM:
		break;
	}
	if (xe >= 63) {
		/* look for valid corner case */
		if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
			return -0x8000000000000000LL;
		/* Set invalid. We will only use overflow for floating
		   point overflow */
		ieee754_setcx(IEEE754_INVALID_OPERATION);
		return ieee754di_overflow(xs);
	}
	/* oh gawd */
	if (xe > SP_FBITS) {
		xm <<= xe - SP_FBITS;
	} else if (xe < SP_FBITS) {
		if (xe < -1) {
			residue = xm;
			round = 0;
			sticky = residue != 0;
			xm = 0;
		} else {
			residue = xm << (32 - SP_FBITS + xe);
			round = (residue >> 31) != 0;
			sticky = (residue << 1) != 0;
			xm >>= SP_FBITS - xe;
		}
		odd = (xm & 0x1) != 0x0;
		switch (ieee754_csr.rm) {
		case FPU_CSR_RN:
			if (round && (sticky || odd))
				xm++;
			break;
		case FPU_CSR_RZ:
			break;
		case FPU_CSR_RU:	/* toward +Infinity */
			if ((round || sticky) && !xs)
				xm++;
			break;
		case FPU_CSR_RD:	/* toward -Infinity */
			if ((round || sticky) && xs)
				xm++;
			break;
		}
		if ((xm >> 63) != 0) {
			/* This can happen after rounding */
			ieee754_setcx(IEEE754_INVALID_OPERATION);
			return ieee754di_overflow(xs);
		}
		if (round || sticky)
			ieee754_setcx(IEEE754_INEXACT);
	}
	if (xs)
		return -xm;
	else
		return xm;
}
Commit	Line	Data
1da177e4 LT	1	/* IEEE754 floating point arithmetic
	2	* single precision
	3	*/
	4	/*
	5	* MIPS floating point support
	6	* Copyright (C) 1994-2000 Algorithmics Ltd.
1da177e4	7	*
1da177e4 LT	8	* This program is free software; you can distribute it and/or modify it
	9	* under the terms of the GNU General Public License (Version 2) as
	10	* published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope it will be useful, but WITHOUT
	13	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	14	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	15	* for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License along
	18	* with this program; if not, write to the Free Software Foundation, Inc.,
3f7cac41	19	* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1da177e4 LT	20	*/
1da177e4 LT	21
1da177e4	22	#include "ieee754sp.h"
b3a7ad2b	23	#include "ieee754dp.h"
1da177e4	24
2209bcb1	25	s64 ieee754sp_tlong(union ieee754sp x)
1da177e4	26	{
3f7cac41 RB	27	u32 residue;
	28	int round;
	29	int sticky;
	30	int odd;
	31
1da177e4 LT	32	COMPXDP; /* <-- need 64-bit mantissa tmp */
1da177e4 LT	33
9e8bad1f	34	ieee754_clearcx();
1da177e4 LT	35
	36	EXPLODEXSP;
	37	FLUSHXSP;
	38
	39	switch (xc) {
	40	case IEEE754_CLASS_SNAN:
	41	case IEEE754_CLASS_QNAN:
9e8bad1f	42	ieee754_setcx(IEEE754_INVALID_OPERATION);
90efba36	43	return ieee754di_indef();
3f7cac41	44
90d53a91 MR	45	case IEEE754_CLASS_INF:
	46	ieee754_setcx(IEEE754_INVALID_OPERATION);
	47	return ieee754di_overflow(xs);
	48
1da177e4 LT	49	case IEEE754_CLASS_ZERO:
1da177e4 LT	50	return 0;
3f7cac41	51
1da177e4 LT	52	case IEEE754_CLASS_DNORM:
	53	case IEEE754_CLASS_NORM:
	54	break;
	55	}
	56	if (xe >= 63) {
	57	/* look for valid corner case */
	58	if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
	59	return -0x8000000000000000LL;
	60	/* Set invalid. We will only use overflow for floating
	61	point overflow */
9e8bad1f	62	ieee754_setcx(IEEE754_INVALID_OPERATION);
90d53a91	63	return ieee754di_overflow(xs);
1da177e4 LT	64	}
1da177e4 LT	65	/* oh gawd */
ad8fb553 RB	66	if (xe > SP_FBITS) {
	67	xm <<= xe - SP_FBITS;
	68	} else if (xe < SP_FBITS) {
1da177e4 LT	69	if (xe < -1) {
	70	residue = xm;
	71	round = 0;
	72	sticky = residue != 0;
	73	xm = 0;
abb86dc5	74	} else {
ad8fb553	75	residue = xm << (32 - SP_FBITS + xe);
1da177e4 LT	76	round = (residue >> 31) != 0;
1da177e4 LT	77	sticky = (residue << 1) != 0;
ad8fb553	78	xm >>= SP_FBITS - xe;
1da177e4 LT	79	}
	80	odd = (xm & 0x1) != 0x0;
	81	switch (ieee754_csr.rm) {
56a64733	82	case FPU_CSR_RN:
1da177e4 LT	83	if (round && (sticky \|\| odd))
	84	xm++;
	85	break;
56a64733	86	case FPU_CSR_RZ:
1da177e4	87	break;
56a64733	88	case FPU_CSR_RU: /* toward +Infinity */
1da177e4 LT	89	if ((round \|\| sticky) && !xs)
	90	xm++;
	91	break;
56a64733	92	case FPU_CSR_RD: /* toward -Infinity */
1da177e4 LT	93	if ((round \|\| sticky) && xs)
	94	xm++;
	95	break;
	96	}
	97	if ((xm >> 63) != 0) {
	98	/* This can happen after rounding */
9e8bad1f	99	ieee754_setcx(IEEE754_INVALID_OPERATION);
90d53a91	100	return ieee754di_overflow(xs);
1da177e4 LT	101	}
1da177e4 LT	102	if (round \|\| sticky)
9e8bad1f	103	ieee754_setcx(IEEE754_INEXACT);
1da177e4 LT	104	}
	105	if (xs)
	106	return -xm;
	107	else
	108	return xm;
	109	}