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_mul(union ieee754sp x
, union ieee754sp y
)
49 switch (CLPAIR(xc
, yc
)) {
50 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_QNAN
):
51 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_SNAN
):
52 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_SNAN
):
53 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_SNAN
):
54 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_SNAN
):
55 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_SNAN
):
56 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_SNAN
):
57 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_ZERO
):
58 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_NORM
):
59 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_DNORM
):
60 case CLPAIR(IEEE754_CLASS_SNAN
, IEEE754_CLASS_INF
):
61 ieee754_setcx(IEEE754_INVALID_OPERATION
);
62 return ieee754sp_nanxcpt(ieee754sp_indef());
64 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_QNAN
):
65 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_QNAN
):
66 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_QNAN
):
67 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_QNAN
):
70 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_QNAN
):
71 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_ZERO
):
72 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_NORM
):
73 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_DNORM
):
74 case CLPAIR(IEEE754_CLASS_QNAN
, IEEE754_CLASS_INF
):
81 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_ZERO
):
82 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_INF
):
83 ieee754_setcx(IEEE754_INVALID_OPERATION
);
84 return ieee754sp_indef();
86 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_INF
):
87 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_INF
):
88 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_NORM
):
89 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_DNORM
):
90 case CLPAIR(IEEE754_CLASS_INF
, IEEE754_CLASS_INF
):
91 return ieee754sp_inf(xs
^ ys
);
93 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_ZERO
):
94 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_NORM
):
95 case CLPAIR(IEEE754_CLASS_ZERO
, IEEE754_CLASS_DNORM
):
96 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_ZERO
):
97 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_ZERO
):
98 return ieee754sp_zero(xs
^ ys
);
101 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_DNORM
):
104 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_DNORM
):
108 case CLPAIR(IEEE754_CLASS_DNORM
, IEEE754_CLASS_NORM
):
112 case CLPAIR(IEEE754_CLASS_NORM
, IEEE754_CLASS_NORM
):
115 /* rm = xm * ym, re = xe+ye basically */
116 assert(xm
& SP_HIDDEN_BIT
);
117 assert(ym
& SP_HIDDEN_BIT
);
122 /* shunt to top of word */
123 xm
<<= 32 - (SP_FBITS
+ 1);
124 ym
<<= 32 - (SP_FBITS
+ 1);
127 * Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
134 lrm
= lxm
* lym
; /* 16 * 16 => 32 */
135 hrm
= hxm
* hym
; /* 16 * 16 => 32 */
137 t
= lxm
* hym
; /* 16 * 16 => 32 */
138 at
= lrm
+ (t
<< 16);
141 hrm
= hrm
+ (t
>> 16);
143 t
= hxm
* lym
; /* 16 * 16 => 32 */
144 at
= lrm
+ (t
<< 16);
147 hrm
= hrm
+ (t
>> 16);
149 rm
= hrm
| (lrm
!= 0);
152 * Sticky shift down to normal rounding precision.
155 rm
= (rm
>> (32 - (SP_FBITS
+ 1 + 3))) |
156 ((rm
<< (SP_FBITS
+ 1 + 3)) != 0);
159 rm
= (rm
>> (32 - (SP_FBITS
+ 1 + 3 + 1))) |
160 ((rm
<< (SP_FBITS
+ 1 + 3 + 1)) != 0);
162 assert(rm
& (SP_HIDDEN_BIT
<< 3));
164 return ieee754sp_format(rs
, re
, rm
);