[net-next-2.6.git] / arch / mips / math-emu / sp_add.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.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 */


#include "ieee754sp.h"

ieee754sp ieee754sp_add(ieee754sp x, ieee754sp y)
{
	COMPXSP;
	COMPYSP;

	EXPLODEXSP;
	EXPLODEYSP;

	CLEARCX;

	FLUSHXSP;
	FLUSHYSP;

	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):
		SETCX(IEEE754_INVALID_OPERATION);
		return ieee754sp_nanxcpt(ieee754sp_indef(), "add", x, y);

	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):
		if (xs == ys)
			return x;
		SETCX(IEEE754_INVALID_OPERATION);
		return ieee754sp_xcpt(ieee754sp_indef(), "add", x, y);

	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 y;

	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 x;

		/* Zero handling
		 */

	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
		if (xs == ys)
			return x;
		else
			return ieee754sp_zero(ieee754_csr.rm ==
					      IEEE754_RD);

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

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

	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
		SPDNORMX;

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

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

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

	/* provide guard,round and stick bit space */
	xm <<= 3;
	ym <<= 3;

	if (xe > ye) {
		/* have to shift y fraction right to align
		 */
		int s = xe - ye;
		SPXSRSYn(s);
	} else if (ye > xe) {
		/* have to shift x fraction right to align
		 */
		int s = ye - xe;
		SPXSRSXn(s);
	}
	assert(xe == ye);
	assert(xe <= SP_EMAX);

	if (xs == ys) {
		/* generate 28 bit result of adding two 27 bit numbers
		 * leaving result in xm,xs,xe
		 */
		xm = xm + ym;
		xe = xe;
		xs = xs;

		if (xm >> (SP_MBITS + 1 + 3)) {	/* carry out */
			SPXSRSX1();
		}
	} else {
		if (xm >= ym) {
			xm = xm - ym;
			xe = xe;
			xs = xs;
		} else {
			xm = ym - xm;
			xe = xe;
			xs = ys;
		}
		if (xm == 0)
			return ieee754sp_zero(ieee754_csr.rm ==
					      IEEE754_RD);

		/* normalize in extended single precision */
		while ((xm >> (SP_MBITS + 3)) == 0) {
			xm <<= 1;
			xe--;
		}

	}
	SPNORMRET2(xs, xe, xm, "add", x, y);
}
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 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 "ieee754sp.h"
	28
	29	ieee754sp ieee754sp_add(ieee754sp x, ieee754sp y)
	30	{
	31	COMPXSP;
	32	COMPYSP;
	33
	34	EXPLODEXSP;
	35	EXPLODEYSP;
	36
	37	CLEARCX;
	38
	39	FLUSHXSP;
	40	FLUSHYSP;
	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):
	54	SETCX(IEEE754_INVALID_OPERATION);
	55	return ieee754sp_nanxcpt(ieee754sp_indef(), "add", x, y);
	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):
75	if (xs == ys)
76	return x;
77	SETCX(IEEE754_INVALID_OPERATION);
78	return ieee754sp_xcpt(ieee754sp_indef(), "add", x, y);
79
80	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
81	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
82	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
83	return y;
84
85	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
86	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
87	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
88	return x;
89
90	/* Zero handling
91	*/
92
93	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
94	if (xs == ys)
95	return x;
96	else
97	return ieee754sp_zero(ieee754_csr.rm ==
98	IEEE754_RD);
99
100	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
101	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
102	return x;
103
104	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
105	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
106	return y;
107
108	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
109	SPDNORMX;
110
111	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
112	SPDNORMY;
113	break;
114
115	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
116	SPDNORMX;
117	break;
118
119	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
120	break;
121	}
122	assert(xm & SP_HIDDEN_BIT);
123	assert(ym & SP_HIDDEN_BIT);
124
125	/* provide guard,round and stick bit space */
126	xm <<= 3;
127	ym <<= 3;
128
129	if (xe > ye) {
130	/* have to shift y fraction right to align
131	*/
132	int s = xe - ye;
133	SPXSRSYn(s);
134	} else if (ye > xe) {
135	/* have to shift x fraction right to align
136	*/
137	int s = ye - xe;
138	SPXSRSXn(s);
139	}
140	assert(xe == ye);
141	assert(xe <= SP_EMAX);
142
143	if (xs == ys) {
144	/* generate 28 bit result of adding two 27 bit numbers
145	* leaving result in xm,xs,xe
146	*/
147	xm = xm + ym;
148	xe = xe;
149	xs = xs;
150
151	if (xm >> (SP_MBITS + 1 + 3)) { /* carry out */
152	SPXSRSX1();
153	}
154	} else {
155	if (xm >= ym) {
156	xm = xm - ym;
157	xe = xe;
158	xs = xs;
159	} else {
160	xm = ym - xm;
161	xe = xe;
162	xs = ys;
163	}
164	if (xm == 0)
165	return ieee754sp_zero(ieee754_csr.rm ==
166	IEEE754_RD);
167
168	/* normalize in extended single precision */
169	while ((xm >> (SP_MBITS + 3)) == 0) {
170	xm <<= 1;
171	xe--;
172	}
173
174	}
175	SPNORMRET2(xs, xe, xm, "add", x, y);
176	}