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1da177e4 LT |
1 | /* IEEE754 floating point arithmetic |
2 | * single precision | |
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 "ieee754sp.h" |
23 | ||
2209bcb1 | 24 | union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y) |
1da177e4 | 25 | { |
3f7cac41 RB |
26 | int re; |
27 | int rs; | |
28 | unsigned rm; | |
29 | unsigned short lxm; | |
30 | unsigned short hxm; | |
31 | unsigned short lym; | |
32 | unsigned short hym; | |
33 | unsigned lrm; | |
34 | unsigned hrm; | |
35 | unsigned t; | |
36 | unsigned at; | |
37 | ||
1da177e4 LT |
38 | COMPXSP; |
39 | COMPYSP; | |
40 | ||
41 | EXPLODEXSP; | |
42 | EXPLODEYSP; | |
43 | ||
9e8bad1f | 44 | ieee754_clearcx(); |
1da177e4 LT |
45 | |
46 | FLUSHXSP; | |
47 | FLUSHYSP; | |
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 ieee754sp_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 ieee754sp_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 ieee754sp_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 ieee754sp_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 ieee754sp_zero(xs ^ ys); | |
100 | ||
101 | ||
102 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): | |
103 | SPDNORMX; | |
104 | ||
105 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): | |
106 | SPDNORMY; | |
107 | break; | |
108 | ||
109 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): | |
110 | SPDNORMX; | |
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 & SP_HIDDEN_BIT); |
118 | assert(ym & SP_HIDDEN_BIT); | |
119 | ||
3f7cac41 RB |
120 | re = xe + ye; |
121 | rs = xs ^ ys; | |
122 | ||
123 | /* shunt to top of word */ | |
124 | xm <<= 32 - (SP_FBITS + 1); | |
125 | ym <<= 32 - (SP_FBITS + 1); | |
126 | ||
127 | /* | |
128 | * Multiply 32 bits xm, ym to give high 32 bits rm with stickness. | |
129 | */ | |
130 | lxm = xm & 0xffff; | |
131 | hxm = xm >> 16; | |
132 | lym = ym & 0xffff; | |
133 | hym = ym >> 16; | |
134 | ||
135 | lrm = lxm * lym; /* 16 * 16 => 32 */ | |
136 | hrm = hxm * hym; /* 16 * 16 => 32 */ | |
137 | ||
138 | t = lxm * hym; /* 16 * 16 => 32 */ | |
139 | at = lrm + (t << 16); | |
140 | hrm += at < lrm; | |
141 | lrm = at; | |
142 | hrm = hrm + (t >> 16); | |
143 | ||
144 | t = hxm * lym; /* 16 * 16 => 32 */ | |
145 | at = lrm + (t << 16); | |
146 | hrm += at < lrm; | |
147 | lrm = at; | |
148 | hrm = hrm + (t >> 16); | |
149 | ||
150 | rm = hrm | (lrm != 0); | |
151 | ||
152 | /* | |
153 | * Sticky shift down to normal rounding precision. | |
154 | */ | |
155 | if ((int) rm < 0) { | |
156 | rm = (rm >> (32 - (SP_FBITS + 1 + 3))) | | |
157 | ((rm << (SP_FBITS + 1 + 3)) != 0); | |
158 | re++; | |
159 | } else { | |
160 | rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) | | |
161 | ((rm << (SP_FBITS + 1 + 3 + 1)) != 0); | |
1da177e4 | 162 | } |
3f7cac41 RB |
163 | assert(rm & (SP_HIDDEN_BIT << 3)); |
164 | ||
165 | return ieee754sp_format(rs, re, rm); | |
1da177e4 | 166 | } |