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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_div(union ieee754sp x, union ieee754sp y) |
1da177e4 | 25 | { |
3f7cac41 RB |
26 | unsigned rm; |
27 | int re; | |
28 | unsigned bm; | |
29 | ||
1da177e4 LT |
30 | COMPXSP; |
31 | COMPYSP; | |
32 | ||
33 | EXPLODEXSP; | |
34 | EXPLODEYSP; | |
35 | ||
9e8bad1f | 36 | ieee754_clearcx(); |
1da177e4 LT |
37 | |
38 | FLUSHXSP; | |
39 | FLUSHYSP; | |
40 | ||
41 | switch (CLPAIR(xc, yc)) { | |
42 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): | |
43 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): | |
44 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): | |
45 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): | |
46 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): | |
47 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): | |
48 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): | |
49 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): | |
50 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): | |
51 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): | |
52 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): | |
9e8bad1f | 53 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
90efba36 | 54 | return ieee754sp_nanxcpt(ieee754sp_indef()); |
1da177e4 LT |
55 | |
56 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): | |
57 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): | |
58 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): | |
59 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): | |
60 | return y; | |
61 | ||
62 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): | |
63 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): | |
64 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): | |
65 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): | |
66 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): | |
67 | return x; | |
68 | ||
69 | ||
3f7cac41 RB |
70 | /* |
71 | * Infinity handling | |
72 | */ | |
1da177e4 | 73 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): |
9e8bad1f | 74 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
90efba36 | 75 | return ieee754sp_indef(); |
1da177e4 LT |
76 | |
77 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): | |
78 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): | |
79 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): | |
80 | return ieee754sp_zero(xs ^ ys); | |
81 | ||
82 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): | |
83 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): | |
84 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): | |
85 | return ieee754sp_inf(xs ^ ys); | |
86 | ||
3f7cac41 RB |
87 | /* |
88 | * Zero handling | |
89 | */ | |
1da177e4 | 90 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): |
9e8bad1f | 91 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
90efba36 | 92 | return ieee754sp_indef(); |
1da177e4 LT |
93 | |
94 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): | |
95 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): | |
9e8bad1f | 96 | ieee754_setcx(IEEE754_ZERO_DIVIDE); |
90efba36 | 97 | return ieee754sp_inf(xs ^ ys); |
1da177e4 LT |
98 | |
99 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): | |
100 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): | |
101 | return ieee754sp_zero(xs == ys ? 0 : 1); | |
102 | ||
103 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): | |
104 | SPDNORMX; | |
105 | ||
106 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): | |
107 | SPDNORMY; | |
108 | break; | |
109 | ||
110 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): | |
111 | SPDNORMX; | |
112 | break; | |
113 | ||
114 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): | |
115 | break; | |
116 | } | |
117 | assert(xm & SP_HIDDEN_BIT); | |
118 | assert(ym & SP_HIDDEN_BIT); | |
119 | ||
120 | /* provide rounding space */ | |
121 | xm <<= 3; | |
122 | ym <<= 3; | |
123 | ||
3f7cac41 | 124 | /* now the dirty work */ |
1da177e4 | 125 | |
3f7cac41 RB |
126 | rm = 0; |
127 | re = xe - ye; | |
1da177e4 | 128 | |
3f7cac41 RB |
129 | for (bm = SP_MBIT(SP_FBITS + 2); bm; bm >>= 1) { |
130 | if (xm >= ym) { | |
131 | xm -= ym; | |
132 | rm |= bm; | |
133 | if (xm == 0) | |
134 | break; | |
1da177e4 | 135 | } |
3f7cac41 RB |
136 | xm <<= 1; |
137 | } | |
138 | ||
139 | rm <<= 1; | |
140 | if (xm) | |
141 | rm |= 1; /* have remainder, set sticky */ | |
1da177e4 | 142 | |
3f7cac41 RB |
143 | assert(rm); |
144 | ||
145 | /* normalise rm to rounding precision ? | |
146 | */ | |
147 | while ((rm >> (SP_FBITS + 3)) == 0) { | |
148 | rm <<= 1; | |
149 | re--; | |
1da177e4 | 150 | } |
3f7cac41 RB |
151 | |
152 | return ieee754sp_format(xs == ys ? 0 : 1, re, rm); | |
1da177e4 | 153 | } |