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gerrit-public.fairphone.software / kernel / msm-4.19 / ce6795593ba572ace9195b8e573e15f86fb411dd / . / arch / mips / math-emu / sp_fmax.c
blob: 22019ed691df10541c35b94535835f38c619a7b9 [file] [log] [blame]
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]1/*
2 * IEEE754 floating point arithmetic
3 * single precision: MAX{,A}.f
4 * MAX : Scalar Floating-Point Maximum
5 * MAXA: Scalar Floating-Point argument with Maximum Absolute Value
6 *
7 * MAX.S : FPR[fd] = maxNum(FPR[fs],FPR[ft])
8 * MAXA.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_fmax(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
Aleksandar Markovice78bf0d2017-07-27 18:08:48 +0200[diff] [blame]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 */
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 ? y : x;
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 ? x : y;
93
94 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
Aleksandar Markovic15560a52017-07-27 18:08:49 +0200[diff] [blame]95 return ieee754sp_zero(xs & ys);
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]96
97 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
98 SPDNORMX;
Aleksandar Markovic2a14b212017-11-02 12:14:05 +0100[diff] [blame]99 /* fall through */
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 y;
117 else if (xs < ys)
118 return x;
119
Aleksandar Markovicaabf5cf2017-07-27 18:08:50 +0200[diff] [blame]120 /* Signs of inputs are equal, let's compare exponents */
121 if (xs == 0) {
122 /* Inputs are both positive */
123 if (xe > ye)
124 return x;
125 else if (xe < ye)
126 return y;
127 } else {
128 /* Inputs are both negative */
129 if (xe > ye)
130 return y;
131 else if (xe < ye)
132 return x;
133 }
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]134
Aleksandar Markovicaabf5cf2017-07-27 18:08:50 +0200[diff] [blame]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 y;
140 return x;
141 }
142 /* Inputs are both negative, with equal signs and exponents */
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]143 if (xm <= ym)
Aleksandar Markovicaabf5cf2017-07-27 18:08:50 +0200[diff] [blame]144 return x;
145 return y;
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]146}
147
148union ieee754sp ieee754sp_fmaxa(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
Aleksandar Markovice78bf0d2017-07-27 18:08:48 +0200[diff] [blame]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 */
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 */
Aleksandar Markovic3444c4e2017-07-27 18:08:52 +0200[diff] [blame]206 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
207 return ieee754sp_inf(xs & ys);
208
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 x;
215
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 y;
222
223 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
Aleksandar Markovic15560a52017-07-27 18:08:49 +0200[diff] [blame]224 return ieee754sp_zero(xs & ys);
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]225
226 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
227 SPDNORMX;
Aleksandar Markovic2a14b212017-11-02 12:14:05 +0100[diff] [blame]228 /* fall through */
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]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 x;
246 else if (xe < ye)
247 return y;
248
249 /* Compare mantissa */
Aleksandar Markovic1a41b3b2017-07-27 18:08:51 +0200[diff] [blame]250 if (xm < ym)
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]251 return y;
Aleksandar Markovic1a41b3b2017-07-27 18:08:51 +0200[diff] [blame]252 else if (xm > ym)
253 return x;
254 else if (xs == 0)
255 return x;
256 return y;
Markos Chandrasa79f5f92015-08-13 09:56:36 +0200[diff] [blame]257}