1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /*
3 * IEEE754 floating point arithmetic
4 * double precision: MIN{,A}.f
5 * MIN : Scalar Floating-Point Minimum
6 * MINA: Scalar Floating-Point argument with M
7 *
8 * MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft])
9 * MINA.D: FPR[fd] = maxNumMag(FPR[fs],FPR[ft]
10 *
11 * MIPS floating point support
12 * Copyright (C) 2015 Imagination Technologies
13 * Author: Markos Chandras <markos.chandras@im
14 */
15
16 #include "ieee754dp.h"
17
18 union ieee754dp ieee754dp_fmax(union ieee754dp
19 {
20 COMPXDP;
21 COMPYDP;
22
23 EXPLODEXDP;
24 EXPLODEYDP;
25
26 FLUSHXDP;
27 FLUSHYDP;
28
29 ieee754_clearcx();
30
31 switch (CLPAIR(xc, yc)) {
32 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
33 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
34 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
35 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
36 case CLPAIR(IEEE754_CLASS_INF, IEEE754
37 return ieee754dp_nanxcpt(y);
38
39 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
40 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
41 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
42 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
43 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
44 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
45 return ieee754dp_nanxcpt(x);
46
47 /*
48 * Quiet NaN handling
49 */
50
51 /*
52 * The case of both inputs quiet Na
53 */
54 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
55 return x;
56
57 /*
58 * The cases of exactly one input q
59 * are here preferred as returned v
60 */
61 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
62 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
63 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
64 case CLPAIR(IEEE754_CLASS_INF, IEEE754
65 return x;
66
67 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
68 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
69 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
70 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
71 return y;
72
73 /*
74 * Infinity and zero handling
75 */
76 case CLPAIR(IEEE754_CLASS_INF, IEEE754
77 case CLPAIR(IEEE754_CLASS_INF, IEEE754
78 case CLPAIR(IEEE754_CLASS_INF, IEEE754
79 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
80 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
81 return xs ? y : x;
82
83 case CLPAIR(IEEE754_CLASS_INF, IEEE754
84 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
85 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
86 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
87 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
88 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
89 return ys ? x : y;
90
91 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
92 return ieee754dp_zero(xs & ys)
93
94 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
95 DPDNORMX;
96 fallthrough;
97 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
98 DPDNORMY;
99 break;
100
101 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
102 DPDNORMX;
103 }
104
105 /* Finally get to do some computation
106
107 assert(xm & DP_HIDDEN_BIT);
108 assert(ym & DP_HIDDEN_BIT);
109
110 /* Compare signs */
111 if (xs > ys)
112 return y;
113 else if (xs < ys)
114 return x;
115
116 /* Signs of inputs are equal, let's co
117 if (xs == 0) {
118 /* Inputs are both positive */
119 if (xe > ye)
120 return x;
121 else if (xe < ye)
122 return y;
123 } else {
124 /* Inputs are both negative */
125 if (xe > ye)
126 return y;
127 else if (xe < ye)
128 return x;
129 }
130
131 /* Signs and exponents of inputs are e
132 if (xs == 0) {
133 /* Inputs are both positive, w
134 if (xm <= ym)
135 return y;
136 return x;
137 }
138 /* Inputs are both negative, with equa
139 if (xm <= ym)
140 return x;
141 return y;
142 }
143
144 union ieee754dp ieee754dp_fmaxa(union ieee754d
145 {
146 COMPXDP;
147 COMPYDP;
148
149 EXPLODEXDP;
150 EXPLODEYDP;
151
152 FLUSHXDP;
153 FLUSHYDP;
154
155 ieee754_clearcx();
156
157 switch (CLPAIR(xc, yc)) {
158 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
159 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
160 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
161 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
162 case CLPAIR(IEEE754_CLASS_INF, IEEE754
163 return ieee754dp_nanxcpt(y);
164
165 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
166 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
167 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
168 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
169 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
170 case CLPAIR(IEEE754_CLASS_SNAN, IEEE75
171 return ieee754dp_nanxcpt(x);
172
173 /*
174 * Quiet NaN handling
175 */
176
177 /*
178 * The case of both inputs quiet Na
179 */
180 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
181 return x;
182
183 /*
184 * The cases of exactly one input q
185 * are here preferred as returned v
186 */
187 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
188 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
189 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
190 case CLPAIR(IEEE754_CLASS_INF, IEEE754
191 return x;
192
193 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
194 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
195 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
196 case CLPAIR(IEEE754_CLASS_QNAN, IEEE75
197 return y;
198
199 /*
200 * Infinity and zero handling
201 */
202 case CLPAIR(IEEE754_CLASS_INF, IEEE754
203 return ieee754dp_inf(xs & ys);
204
205 case CLPAIR(IEEE754_CLASS_INF, IEEE754
206 case CLPAIR(IEEE754_CLASS_INF, IEEE754
207 case CLPAIR(IEEE754_CLASS_INF, IEEE754
208 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
209 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
210 return x;
211
212 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
213 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
214 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
215 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
216 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
217 return y;
218
219 case CLPAIR(IEEE754_CLASS_ZERO, IEEE75
220 return ieee754dp_zero(xs & ys)
221
222 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
223 DPDNORMX;
224 fallthrough;
225 case CLPAIR(IEEE754_CLASS_NORM, IEEE75
226 DPDNORMY;
227 break;
228
229 case CLPAIR(IEEE754_CLASS_DNORM, IEEE7
230 DPDNORMX;
231 }
232
233 /* Finally get to do some computation
234
235 assert(xm & DP_HIDDEN_BIT);
236 assert(ym & DP_HIDDEN_BIT);
237
238 /* Compare exponent */
239 if (xe > ye)
240 return x;
241 else if (xe < ye)
242 return y;
243
244 /* Compare mantissa */
245 if (xm < ym)
246 return y;
247 else if (xm > ym)
248 return x;
249 else if (xs == 0)
250 return x;
251 return y;
252 }
253
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