1/*
  2 * IEEE754 floating point arithmetic
  3 * single precision: MIN{,A}.f
  4 * MIN : Scalar Floating-Point Minimum
  5 * MINA: Scalar Floating-Point argument with Minimum Absolute Value
  6 *
  7 * MIN.S : FPR[fd] = minNum(FPR[fs],FPR[ft])
  8 * MINA.S: 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 "ieee754sp.h"
 20
 21union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y)
 22{
 23	COMPXSP;
 24	COMPYSP;
 25
 26	EXPLODEXSP;
 27	EXPLODEYSP;
 28
 29	FLUSHXSP;
 30	FLUSHYSP;
 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 ieee754sp_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 ieee754sp_nanxcpt(x);
 49
 50	/*
 51	 * Quiet NaN handling
 52	 */
 53
 54	/*
 55	 *    The case of both inputs quiet NaNs
 56	 */
 57	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
 58		return x;
 59
 60	/*
 61	 *    The cases of exactly one input quiet NaN (numbers
 62	 *    are here preferred as returned values to NaNs)
 63	 */
 64	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
 65	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
 66	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
 67	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
 68		return x;
 69
 70	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
 71	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
 72	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
 73	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
 74		return y;
 75
 76	/*
 77	 * Infinity and zero handling
 78	 */
 79	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
 80	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
 81	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 82	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 83	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
 84		return xs ? x : y;
 85
 86	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
 87	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 88	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 89	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 90	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 91	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
 92		return ys ? y : x;
 93
 94	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 95		return ieee754sp_zero(xs | ys);
 96
 97	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
 98		SPDNORMX;
 99		/* fall through */
100
101	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
102		SPDNORMY;
103		break;
104
105	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
106		SPDNORMX;
107	}
108
109	/* Finally get to do some computation */
110
111	assert(xm & SP_HIDDEN_BIT);
112	assert(ym & SP_HIDDEN_BIT);
113
114	/* Compare signs */
115	if (xs > ys)
116		return x;
117	else if (xs < ys)
118		return y;
119
120	/* Signs of inputs are the same, let's compare exponents */
121	if (xs == 0) {
122		/* Inputs are both positive */
123		if (xe > ye)
124			return y;
125		else if (xe < ye)
126			return x;
127	} else {
128		/* Inputs are both negative */
129		if (xe > ye)
130			return x;
131		else if (xe < ye)
132			return y;
133	}
134
135	/* Signs and exponents of inputs are equal, let's compare mantissas */
136	if (xs == 0) {
137		/* Inputs are both positive, with equal signs and exponents */
138		if (xm <= ym)
139			return x;
140		return y;
141	}
142	/* Inputs are both negative, with equal signs and exponents */
143	if (xm <= ym)
144		return y;
145	return x;
146}
147
148union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y)
149{
150	COMPXSP;
151	COMPYSP;
152
153	EXPLODEXSP;
154	EXPLODEYSP;
155
156	FLUSHXSP;
157	FLUSHYSP;
158
159	ieee754_clearcx();
160
161	switch (CLPAIR(xc, yc)) {
162	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
163	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
164	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
165	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
166	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
167		return ieee754sp_nanxcpt(y);
168
169	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
170	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
171	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
172	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
173	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
174	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
175		return ieee754sp_nanxcpt(x);
176
177	/*
178	 * Quiet NaN handling
179	 */
180
181	/*
182	 *    The case of both inputs quiet NaNs
183	 */
184	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
185		return x;
186
187	/*
188	 *    The cases of exactly one input quiet NaN (numbers
189	 *    are here preferred as returned values to NaNs)
190	 */
191	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
192	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
193	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
194	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
195		return x;
196
197	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
198	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
199	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
200	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
201		return y;
202
203	/*
204	 * Infinity and zero handling
205	 */
206	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
207		return ieee754sp_inf(xs | ys);
208
209	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
210	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
211	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
212	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
213	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
214		return y;
215
216	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
217	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
218	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
219	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
220	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
221		return x;
222
223	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
224		return ieee754sp_zero(xs | ys);
225
226	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
227		SPDNORMX;
228		/* fall through */
229
230	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
231		SPDNORMY;
232		break;
233
234	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
235		SPDNORMX;
236	}
237
238	/* Finally get to do some computation */
239
240	assert(xm & SP_HIDDEN_BIT);
241	assert(ym & SP_HIDDEN_BIT);
242
243	/* Compare exponent */
244	if (xe > ye)
245		return y;
246	else if (xe < ye)
247		return x;
248
249	/* Compare mantissa */
250	if (xm < ym)
251		return x;
252	else if (xm > ym)
253		return y;
254	else if (xs == 1)
255		return x;
256	return y;
257}