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1/* IEEE754 floating point arithmetic
2 * double precision: common utilities
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 * This program is free software; you can distribute it and/or modify it
9 * under the terms of the GNU General Public License (Version 2) as
10 * published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * for more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 */
21
22#include "ieee754dp.h"
23
24union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y)
25{
26 int re;
27 int rs;
28 u64 rm;
29 unsigned lxm;
30 unsigned hxm;
31 unsigned lym;
32 unsigned hym;
33 u64 lrm;
34 u64 hrm;
35 u64 t;
36 u64 at;
37
38 COMPXDP;
39 COMPYDP;
40
41 EXPLODEXDP;
42 EXPLODEYDP;
43
44 ieee754_clearcx();
45
46 FLUSHXDP;
47 FLUSHYDP;
48
49 switch (CLPAIR(xc, yc)) {
50 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
51 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
52 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
53 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
54 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
55 return ieee754dp_nanxcpt(y);
56
57 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
58 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
59 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
60 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
61 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
62 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
63 return ieee754dp_nanxcpt(x);
64
65 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
66 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
67 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
68 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
69 return y;
70
71 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
72 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
73 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
74 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
75 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
76 return x;
77
78
79 /*
80 * Infinity handling
81 */
82 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
83 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
84 ieee754_setcx(IEEE754_INVALID_OPERATION);
85 return ieee754dp_indef();
86
87 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
88 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
89 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
90 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
91 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
92 return ieee754dp_inf(xs ^ ys);
93
94 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
95 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
96 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
97 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
98 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
99 return ieee754dp_zero(xs ^ ys);
100
101
102 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
103 DPDNORMX;
104
105 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
106 DPDNORMY;
107 break;
108
109 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
110 DPDNORMX;
111 break;
112
113 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
114 break;
115 }
116 /* rm = xm * ym, re = xe+ye basically */
117 assert(xm & DP_HIDDEN_BIT);
118 assert(ym & DP_HIDDEN_BIT);
119
120 re = xe + ye;
121 rs = xs ^ ys;
122
123 /* shunt to top of word */
124 xm <<= 64 - (DP_FBITS + 1);
125 ym <<= 64 - (DP_FBITS + 1);
126
127 /*
128 * Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
129 */
130
131 /* 32 * 32 => 64 */
132#define DPXMULT(x, y) ((u64)(x) * (u64)y)
133
134 lxm = xm;
135 hxm = xm >> 32;
136 lym = ym;
137 hym = ym >> 32;
138
139 lrm = DPXMULT(lxm, lym);
140 hrm = DPXMULT(hxm, hym);
141
142 t = DPXMULT(lxm, hym);
143
144 at = lrm + (t << 32);
145 hrm += at < lrm;
146 lrm = at;
147
148 hrm = hrm + (t >> 32);
149
150 t = DPXMULT(hxm, lym);
151
152 at = lrm + (t << 32);
153 hrm += at < lrm;
154 lrm = at;
155
156 hrm = hrm + (t >> 32);
157
158 rm = hrm | (lrm != 0);
159
160 /*
161 * Sticky shift down to normal rounding precision.
162 */
163 if ((s64) rm < 0) {
164 rm = (rm >> (64 - (DP_FBITS + 1 + 3))) |
165 ((rm << (DP_FBITS + 1 + 3)) != 0);
166 re++;
167 } else {
168 rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) |
169 ((rm << (DP_FBITS + 1 + 3 + 1)) != 0);
170 }
171 assert(rm & (DP_HIDDEN_BIT << 3));
172
173 return ieee754dp_format(rs, re, rm);
174}
1/* IEEE754 floating point arithmetic
2 * double precision: common utilities
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 * This program is free software; you can distribute it and/or modify it
9 * under the terms of the GNU General Public License (Version 2) as
10 * published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * for more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 */
21
22#include "ieee754dp.h"
23
24union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y)
25{
26 int re;
27 int rs;
28 u64 rm;
29 unsigned lxm;
30 unsigned hxm;
31 unsigned lym;
32 unsigned hym;
33 u64 lrm;
34 u64 hrm;
35 u64 t;
36 u64 at;
37
38 COMPXDP;
39 COMPYDP;
40
41 EXPLODEXDP;
42 EXPLODEYDP;
43
44 ieee754_clearcx();
45
46 FLUSHXDP;
47 FLUSHYDP;
48
49 switch (CLPAIR(xc, yc)) {
50 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
51 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
52 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
53 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
54 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
55 return ieee754dp_nanxcpt(y);
56
57 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
58 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
59 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
60 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
61 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
62 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
63 return ieee754dp_nanxcpt(x);
64
65 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
66 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
67 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
68 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
69 return y;
70
71 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
72 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
73 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
74 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
75 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
76 return x;
77
78
79 /*
80 * Infinity handling
81 */
82 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
83 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
84 ieee754_setcx(IEEE754_INVALID_OPERATION);
85 return ieee754dp_indef();
86
87 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
88 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
89 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
90 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
91 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
92 return ieee754dp_inf(xs ^ ys);
93
94 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
95 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
96 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
97 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
98 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
99 return ieee754dp_zero(xs ^ ys);
100
101
102 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
103 DPDNORMX;
104
105 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
106 DPDNORMY;
107 break;
108
109 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
110 DPDNORMX;
111 break;
112
113 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
114 break;
115 }
116 /* rm = xm * ym, re = xe+ye basically */
117 assert(xm & DP_HIDDEN_BIT);
118 assert(ym & DP_HIDDEN_BIT);
119
120 re = xe + ye;
121 rs = xs ^ ys;
122
123 /* shunt to top of word */
124 xm <<= 64 - (DP_FBITS + 1);
125 ym <<= 64 - (DP_FBITS + 1);
126
127 /*
128 * Multiply 64 bits xm, ym to give high 64 bits rm with stickness.
129 */
130
131 /* 32 * 32 => 64 */
132#define DPXMULT(x, y) ((u64)(x) * (u64)y)
133
134 lxm = xm;
135 hxm = xm >> 32;
136 lym = ym;
137 hym = ym >> 32;
138
139 lrm = DPXMULT(lxm, lym);
140 hrm = DPXMULT(hxm, hym);
141
142 t = DPXMULT(lxm, hym);
143
144 at = lrm + (t << 32);
145 hrm += at < lrm;
146 lrm = at;
147
148 hrm = hrm + (t >> 32);
149
150 t = DPXMULT(hxm, lym);
151
152 at = lrm + (t << 32);
153 hrm += at < lrm;
154 lrm = at;
155
156 hrm = hrm + (t >> 32);
157
158 rm = hrm | (lrm != 0);
159
160 /*
161 * Sticky shift down to normal rounding precision.
162 */
163 if ((s64) rm < 0) {
164 rm = (rm >> (64 - (DP_FBITS + 1 + 3))) |
165 ((rm << (DP_FBITS + 1 + 3)) != 0);
166 re++;
167 } else {
168 rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) |
169 ((rm << (DP_FBITS + 1 + 3 + 1)) != 0);
170 }
171 assert(rm & (DP_HIDDEN_BIT << 3));
172
173 return ieee754dp_format(rs, re, rm);
174}