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gerrit-public.fairphone.software / kernel / msm-4.19 / 8dd0ee651d8aefdc2d8ae0fcc9c68dfc943c9e4c / . / arch / mips / math-emu / sp_fmax.c
blob: 4d000844e48e3d1f7560a3e9dead69ffd9743a2c [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
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 ieee754sp_zero(1);
86
87 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
88 SPDNORMX;
89
90 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
91 SPDNORMY;
92 break;
93
94 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
95 SPDNORMX;
96 }
97
98 /* Finally get to do some computation */
99
100 assert(xm & SP_HIDDEN_BIT);
101 assert(ym & SP_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 ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y)
122{
123 COMPXSP;
124 COMPYSP;
125
126 EXPLODEXSP;
127 EXPLODEYSP;
128
129 FLUSHXSP;
130 FLUSHYSP;
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 ieee754sp_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 ieee754sp_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 ieee754sp_zero(1);
186
187 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
188 SPDNORMX;
189
190 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
191 SPDNORMY;
192 break;
193
194 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
195 SPDNORMX;
196 }
197
198 /* Finally get to do some computation */
199
200 assert(xm & SP_HIDDEN_BIT);
201 assert(ym & SP_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}