1 /* IEEE754 floating point arithmetic
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
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.
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
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.
22 #include "ieee754sp.h"
24 union ieee754sp
ieee754sp_add(union ieee754sp x
, union ieee754sp y
)
39 switch (CLPAIR(xc
, yc
)) {
40 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_QNAN
):
41 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_SNAN
):
42 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_SNAN
):
43 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_SNAN
):
44 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_SNAN
):
45 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_SNAN
):
46 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_SNAN
):
47 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_ZERO
):
48 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_NORM
):
49 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_DNORM
):
50 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_INF
):
51 ieee754_setcx(IEEE754_INVALID_OPERATION
);
52 return ieee754sp_nanxcpt(ieee754sp_indef());
54 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_QNAN
):
55 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_QNAN
):
56 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_QNAN
):
57 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_QNAN
):
60 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_QNAN
):
61 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_ZERO
):
62 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_NORM
):
63 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_DNORM
):
64 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_INF
):
71 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_INF
):
74 ieee754_setcx(IEEE754_INVALID_OPERATION
);
75 return ieee754sp_indef();
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
):
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
):
90 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_ZERO
):
94 return ieee754sp_zero(ieee754_csr
.rm
== FPU_CSR_RD
);
96 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_ZERO
):
97 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_ZERO
):
100 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_NORM
):
101 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_DNORM
):
104 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_DNORM
):
109 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_DNORM
):
113 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_NORM
):
117 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_NORM
):
120 assert(xm
& SP_HIDDEN_BIT
);
121 assert(ym
& SP_HIDDEN_BIT
);
124 * Provide guard, round and stick bit space.
131 * Have to shift y fraction right to align.
135 } else if (ye
> xe
) {
137 * Have to shift x fraction right to align.
143 assert(xe
<= SP_EMAX
);
147 * Generate 28 bit result of adding two 27 bit numbers
148 * leaving result in xm, xs and xe.
154 if (xm
>> (SP_FBITS
+ 1 + 3)) { /* carry out */
168 return ieee754sp_zero(ieee754_csr
.rm
== FPU_CSR_RD
);
171 * Normalize in extended single precision
173 while ((xm
>> (SP_FBITS
+ 3)) == 0) {
179 return ieee754sp_format(xs
, xe
, xm
);