1/*
  2 * IEEE754 floating point arithmetic
  3 * double precision: MIN{,A}.f
  4 * MIN : Scalar Floating-Point Minimum
  5 * MINA: Scalar Floating-Point argument with Minimum Absolute Value
  6 *
  7 * MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft])
  8 * MINA.D: FPR[fd] = maxNumMag(FPR[fs],FPR[ft])
  9 *
 10 * MIPS floating point support
 11 * Copyright (C) 2015 Imagination Technologies, Ltd.
 12 * Author: Markos Chandras <markos.chandras@imgtec.com>
 13 *
 14 *  This program is free software; you can distribute it and/or modify it
 15 *  under the terms of the GNU General Public License as published by the
 16 *  Free Software Foundation; version 2 of the License.
 17 */
 18
 19#include "ieee754dp.h"
 20
 21union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y)
 22{
 23	COMPXDP;
 24	COMPYDP;
 25
 26	EXPLODEXDP;
 27	EXPLODEYDP;
 28
 29	FLUSHXDP;
 30	FLUSHYDP;
 31
 32	ieee754_clearcx();
 33
 34	switch (CLPAIR(xc, yc)) {
 35	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
 36	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
 37	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
 38	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
 39	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
 40		return ieee754dp_nanxcpt(y);
 41
 42	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
 43	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
 44	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
 45	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
 46	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
 47	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
 48		return ieee754dp_nanxcpt(x);
 49
 50	/* numbers are preferred to NaNs */
 51	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
 52	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
 53	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
 54	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
 55		return x;
 56
 57	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
 58	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
 59	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
 60	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
 61	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
 62		return y;
 63
 64	/*
 65	 * Infinity and zero handling
 66	 */
 67	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
 68	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
 69	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 70	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 71	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
 72		return xs ? y : x;
 73
 74	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
 75	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 76	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 77	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 78	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 79	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
 80		return ys ? x : y;
 81
 82	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 83		if (xs == ys)
 84			return x;
 85		return ieee754dp_zero(1);
 86
 87	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
 88		DPDNORMX;
 89
 90	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
 91		DPDNORMY;
 92		break;
 93
 94	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
 95		DPDNORMX;
 96	}
 97
 98	/* Finally get to do some computation */
 99
100	assert(xm & DP_HIDDEN_BIT);
101	assert(ym & DP_HIDDEN_BIT);
102
103	/* Compare signs */
104	if (xs > ys)
105		return y;
106	else if (xs < ys)
107		return x;
108
109	/* Compare exponent */
110	if (xe > ye)
111		return x;
112	else if (xe < ye)
113		return y;
114
115	/* Compare mantissa */
116	if (xm <= ym)
117		return y;
118	return x;
119}
120
121union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y)
122{
123	COMPXDP;
124	COMPYDP;
125
126	EXPLODEXDP;
127	EXPLODEYDP;
128
129	FLUSHXDP;
130	FLUSHYDP;
131
132	ieee754_clearcx();
133
134	switch (CLPAIR(xc, yc)) {
135	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
136	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
137	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
138	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
139	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
140		return ieee754dp_nanxcpt(y);
141
142	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
143	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
144	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
145	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
146	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
147	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
148		return ieee754dp_nanxcpt(x);
149
150	/* numbers are preferred to NaNs */
151	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
152	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
153	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
154	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
155		return x;
156
157	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
158	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
159	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
160	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
161	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
162		return y;
163
164	/*
165	 * Infinity and zero handling
166	 */
167	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
168	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
169	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
170	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
171	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
172		return x;
173
174	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
175	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
176	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
177	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
178	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
179	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
180		return y;
181
182	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
183		if (xs == ys)
184			return x;
185		return ieee754dp_zero(1);
186
187	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
188		DPDNORMX;
189
190	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
191		DPDNORMY;
192		break;
193
194	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
195		DPDNORMX;
196	}
197
198	/* Finally get to do some computation */
199
200	assert(xm & DP_HIDDEN_BIT);
201	assert(ym & DP_HIDDEN_BIT);
202
203	/* Compare exponent */
204	if (xe > ye)
205		return x;
206	else if (xe < ye)
207		return y;
208
209	/* Compare mantissa */
210	if (xm <= ym)
211		return y;
212	return x;
213}