1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * IEEE754 floating point arithmetic
  4 * single precision: MIN{,A}.f
  5 * MIN : Scalar Floating-Point Minimum
  6 * MINA: Scalar Floating-Point argument with Minimum Absolute Value
  7 *
  8 * MIN.S : FPR[fd] = minNum(FPR[fs],FPR[ft])
  9 * MINA.S: FPR[fd] = maxNumMag(FPR[fs],FPR[ft])
 10 *
 11 * MIPS floating point support
 12 * Copyright (C) 2015 Imagination Technologies, Ltd.
 13 * Author: Markos Chandras <markos.chandras@imgtec.com>
 14 */
 15
 16#include "ieee754sp.h"
 17
 18union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y)
 19{
 20	COMPXSP;
 21	COMPYSP;
 22
 23	EXPLODEXSP;
 24	EXPLODEYSP;
 25
 26	FLUSHXSP;
 27	FLUSHYSP;
 28
 29	ieee754_clearcx();
 30
 31	switch (CLPAIR(xc, yc)) {
 32	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
 33	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
 34	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
 35	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
 36	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
 37		return ieee754sp_nanxcpt(y);
 38
 39	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
 40	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
 41	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
 42	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
 43	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
 44	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
 45		return ieee754sp_nanxcpt(x);
 46
 47	/*
 48	 * Quiet NaN handling
 49	 */
 50
 51	/*
 52	 *    The case of both inputs quiet NaNs
 53	 */
 54	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
 55		return x;
 56
 57	/*
 58	 *    The cases of exactly one input quiet NaN (numbers
 59	 *    are here preferred as returned values to NaNs)
 60	 */
 61	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
 62	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
 63	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
 64	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
 65		return x;
 66
 67	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
 68	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
 69	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
 70	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
 71		return y;
 72
 73	/*
 74	 * Infinity and zero handling
 75	 */
 76	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
 77	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
 78	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 79	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 80	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
 81		return xs ? x : y;
 82
 83	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
 84	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 85	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 86	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 87	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 88	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
 89		return ys ? y : x;
 90
 91	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 92		return ieee754sp_zero(xs | ys);
 93
 94	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
 95		SPDNORMX;
 96		fallthrough;
 97	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
 98		SPDNORMY;
 99		break;
100
101	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
102		SPDNORMX;
103	}
104
105	/* Finally get to do some computation */
106
107	assert(xm & SP_HIDDEN_BIT);
108	assert(ym & SP_HIDDEN_BIT);
109
110	/* Compare signs */
111	if (xs > ys)
112		return x;
113	else if (xs < ys)
114		return y;
115
116	/* Signs of inputs are the same, let's compare exponents */
117	if (xs == 0) {
118		/* Inputs are both positive */
119		if (xe > ye)
120			return y;
121		else if (xe < ye)
122			return x;
123	} else {
124		/* Inputs are both negative */
125		if (xe > ye)
126			return x;
127		else if (xe < ye)
128			return y;
129	}
130
131	/* Signs and exponents of inputs are equal, let's compare mantissas */
132	if (xs == 0) {
133		/* Inputs are both positive, with equal signs and exponents */
134		if (xm <= ym)
135			return x;
136		return y;
137	}
138	/* Inputs are both negative, with equal signs and exponents */
139	if (xm <= ym)
140		return y;
141	return x;
142}
143
144union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y)
145{
146	COMPXSP;
147	COMPYSP;
148
149	EXPLODEXSP;
150	EXPLODEYSP;
151
152	FLUSHXSP;
153	FLUSHYSP;
154
155	ieee754_clearcx();
156
157	switch (CLPAIR(xc, yc)) {
158	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
159	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
160	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
161	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
162	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
163		return ieee754sp_nanxcpt(y);
164
165	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
166	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
167	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
168	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
169	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
170	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
171		return ieee754sp_nanxcpt(x);
172
173	/*
174	 * Quiet NaN handling
175	 */
176
177	/*
178	 *    The case of both inputs quiet NaNs
179	 */
180	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
181		return x;
182
183	/*
184	 *    The cases of exactly one input quiet NaN (numbers
185	 *    are here preferred as returned values to NaNs)
186	 */
187	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
188	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
189	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
190	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
191		return x;
192
193	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
194	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
195	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
196	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
197		return y;
198
199	/*
200	 * Infinity and zero handling
201	 */
202	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
203		return ieee754sp_inf(xs | ys);
204
205	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
206	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
207	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
208	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
209	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
210		return y;
211
212	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
213	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
214	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
215	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
216	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
217		return x;
218
219	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
220		return ieee754sp_zero(xs | ys);
221
222	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
223		SPDNORMX;
224		fallthrough;
225	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
226		SPDNORMY;
227		break;
228
229	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
230		SPDNORMX;
231	}
232
233	/* Finally get to do some computation */
234
235	assert(xm & SP_HIDDEN_BIT);
236	assert(ym & SP_HIDDEN_BIT);
237
238	/* Compare exponent */
239	if (xe > ye)
240		return y;
241	else if (xe < ye)
242		return x;
243
244	/* Compare mantissa */
245	if (xm < ym)
246		return x;
247	else if (xm > ym)
248		return y;
249	else if (xs == 1)
250		return x;
251	return y;
252}