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a79f5f9b MC |
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 | ||
21 | union 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 | ||
e78bf0dc AM |
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 | */ | |
a79f5f9b MC |
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 | ||
a79f5f9b MC |
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): | |
15560a58 | 95 | return ieee754sp_zero(xs & ys); |
a79f5f9b MC |
96 | |
97 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): | |
98 | SPDNORMX; | |
99 | ||
100 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): | |
101 | SPDNORMY; | |
102 | break; | |
103 | ||
104 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): | |
105 | SPDNORMX; | |
106 | } | |
107 | ||
108 | /* Finally get to do some computation */ | |
109 | ||
110 | assert(xm & SP_HIDDEN_BIT); | |
111 | assert(ym & SP_HIDDEN_BIT); | |
112 | ||
113 | /* Compare signs */ | |
114 | if (xs > ys) | |
115 | return y; | |
116 | else if (xs < ys) | |
117 | return x; | |
118 | ||
aabf5cf0 AM |
119 | /* Signs of inputs are equal, let's compare exponents */ |
120 | if (xs == 0) { | |
121 | /* Inputs are both positive */ | |
122 | if (xe > ye) | |
123 | return x; | |
124 | else if (xe < ye) | |
125 | return y; | |
126 | } else { | |
127 | /* Inputs are both negative */ | |
128 | if (xe > ye) | |
129 | return y; | |
130 | else if (xe < ye) | |
131 | return x; | |
132 | } | |
a79f5f9b | 133 | |
aabf5cf0 AM |
134 | /* Signs and exponents of inputs are equal, let's compare mantissas */ |
135 | if (xs == 0) { | |
136 | /* Inputs are both positive, with equal signs and exponents */ | |
137 | if (xm <= ym) | |
138 | return y; | |
139 | return x; | |
140 | } | |
141 | /* Inputs are both negative, with equal signs and exponents */ | |
a79f5f9b | 142 | if (xm <= ym) |
aabf5cf0 AM |
143 | return x; |
144 | return y; | |
a79f5f9b MC |
145 | } |
146 | ||
147 | union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y) | |
148 | { | |
149 | COMPXSP; | |
150 | COMPYSP; | |
151 | ||
152 | EXPLODEXSP; | |
153 | EXPLODEYSP; | |
154 | ||
155 | FLUSHXSP; | |
156 | FLUSHYSP; | |
157 | ||
158 | ieee754_clearcx(); | |
159 | ||
160 | switch (CLPAIR(xc, yc)) { | |
161 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): | |
162 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): | |
163 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): | |
164 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): | |
165 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): | |
166 | return ieee754sp_nanxcpt(y); | |
167 | ||
168 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): | |
169 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): | |
170 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): | |
171 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): | |
172 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): | |
173 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): | |
174 | return ieee754sp_nanxcpt(x); | |
175 | ||
e78bf0dc AM |
176 | /* |
177 | * Quiet NaN handling | |
178 | */ | |
179 | ||
180 | /* | |
181 | * The case of both inputs quiet NaNs | |
182 | */ | |
183 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): | |
184 | return x; | |
185 | ||
186 | /* | |
187 | * The cases of exactly one input quiet NaN (numbers | |
188 | * are here preferred as returned values to NaNs) | |
189 | */ | |
a79f5f9b MC |
190 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): |
191 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): | |
192 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): | |
193 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): | |
194 | return x; | |
195 | ||
a79f5f9b MC |
196 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): |
197 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): | |
198 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): | |
199 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): | |
200 | return y; | |
201 | ||
202 | /* | |
203 | * Infinity and zero handling | |
204 | */ | |
3444c4eb AM |
205 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): |
206 | return ieee754sp_inf(xs & ys); | |
207 | ||
a79f5f9b MC |
208 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): |
209 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): | |
210 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): | |
211 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): | |
212 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): | |
213 | return x; | |
214 | ||
a79f5f9b MC |
215 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): |
216 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): | |
217 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): | |
218 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): | |
219 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): | |
220 | return y; | |
221 | ||
222 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): | |
15560a58 | 223 | return ieee754sp_zero(xs & ys); |
a79f5f9b MC |
224 | |
225 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): | |
226 | SPDNORMX; | |
227 | ||
228 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): | |
229 | SPDNORMY; | |
230 | break; | |
231 | ||
232 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): | |
233 | SPDNORMX; | |
234 | } | |
235 | ||
236 | /* Finally get to do some computation */ | |
237 | ||
238 | assert(xm & SP_HIDDEN_BIT); | |
239 | assert(ym & SP_HIDDEN_BIT); | |
240 | ||
241 | /* Compare exponent */ | |
242 | if (xe > ye) | |
243 | return x; | |
244 | else if (xe < ye) | |
245 | return y; | |
246 | ||
247 | /* Compare mantissa */ | |
1a41b3b4 | 248 | if (xm < ym) |
a79f5f9b | 249 | return y; |
1a41b3b4 AM |
250 | else if (xm > ym) |
251 | return x; | |
252 | else if (xs == 0) | |
253 | return x; | |
254 | return y; | |
a79f5f9b | 255 | } |