Commit | Line | Data |
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1da177e4 LT |
1 | /* IEEE754 floating point arithmetic |
2 | * double precision: common utilities | |
3 | */ | |
4 | /* | |
5 | * MIPS floating point support | |
6 | * Copyright (C) 1994-2000 Algorithmics Ltd. | |
1da177e4 | 7 | * |
1da177e4 LT |
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., | |
3f7cac41 | 19 | * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
1da177e4 LT |
20 | */ |
21 | ||
1da177e4 LT |
22 | #include "ieee754dp.h" |
23 | ||
2209bcb1 | 24 | union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y) |
1da177e4 | 25 | { |
3f7cac41 RB |
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 | ||
1da177e4 LT |
38 | COMPXDP; |
39 | COMPYDP; | |
40 | ||
41 | EXPLODEXDP; | |
42 | EXPLODEYDP; | |
43 | ||
9e8bad1f | 44 | ieee754_clearcx(); |
1da177e4 LT |
45 | |
46 | FLUSHXDP; | |
47 | FLUSHYDP; | |
48 | ||
49 | switch (CLPAIR(xc, yc)) { | |
1da177e4 | 50 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): |
1da177e4 LT |
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): | |
d5afa7e9 MR |
55 | return ieee754dp_nanxcpt(y); |
56 | ||
57 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): | |
58 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): | |
1da177e4 LT |
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): | |
d5afa7e9 | 63 | return ieee754dp_nanxcpt(x); |
1da177e4 LT |
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 | ||
3f7cac41 RB |
79 | /* |
80 | * Infinity handling | |
81 | */ | |
1da177e4 LT |
82 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): |
83 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): | |
9e8bad1f | 84 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
90efba36 | 85 | return ieee754dp_indef(); |
1da177e4 LT |
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 | } | |
25985edc | 116 | /* rm = xm * ym, re = xe+ye basically */ |
1da177e4 LT |
117 | assert(xm & DP_HIDDEN_BIT); |
118 | assert(ym & DP_HIDDEN_BIT); | |
1da177e4 | 119 | |
3f7cac41 RB |
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); | |
1da177e4 | 126 | |
3f7cac41 | 127 | /* |
95bff241 | 128 | * Multiply 64 bits xm, ym to give high 64 bits rm with stickness. |
3f7cac41 | 129 | */ |
1da177e4 | 130 | |
3f7cac41 | 131 | /* 32 * 32 => 64 */ |
21a151d8 | 132 | #define DPXMULT(x, y) ((u64)(x) * (u64)y) |
1da177e4 | 133 | |
3f7cac41 RB |
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); | |
5c18c936 | 166 | re++; |
3f7cac41 RB |
167 | } else { |
168 | rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) | | |
169 | ((rm << (DP_FBITS + 1 + 3 + 1)) != 0); | |
1da177e4 | 170 | } |
3f7cac41 RB |
171 | assert(rm & (DP_HIDDEN_BIT << 3)); |
172 | ||
173 | return ieee754dp_format(rs, re, rm); | |
1da177e4 | 174 | } |