1 /* IEEE754 floating point arithmetic
2 * double precision: common utilities
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 * ########################################################################
10 * This program is free software; you can distribute it and/or modify it
11 * under the terms of the GNU General Public License (Version 2) as
12 * published by the Free Software Foundation.
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
23 * ########################################################################
27 #include <linux/kernel.h>
28 #include "ieee754dp.h"
30 int ieee754dp_tint(ieee754dp x)
40 case IEEE754_CLASS_SNAN:
41 case IEEE754_CLASS_QNAN:
42 case IEEE754_CLASS_INF:
43 SETCX(IEEE754_INVALID_OPERATION);
44 return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
45 case IEEE754_CLASS_ZERO:
47 case IEEE754_CLASS_DNORM:
48 case IEEE754_CLASS_NORM:
52 /* Set invalid. We will only use overflow for floating
54 SETCX(IEEE754_INVALID_OPERATION);
55 return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
60 } else if (xe < DP_MBITS) {
69 sticky = residue != 0;
72 residue = xm << (64 - DP_MBITS + xe);
73 round = (residue >> 63) != 0;
74 sticky = (residue << 1) != 0;
77 /* Note: At this point upper 32 bits of xm are guaranteed
79 odd = (xm & 0x1) != 0x0;
80 switch (ieee754_csr.rm) {
82 if (round && (sticky || odd))
87 case IEEE754_RU: /* toward +Infinity */
88 if ((round || sticky) && !xs)
91 case IEEE754_RD: /* toward -Infinity */
92 if ((round || sticky) && xs)
96 /* look for valid corner case 0x80000000 */
97 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
98 /* This can happen after rounding */
99 SETCX(IEEE754_INVALID_OPERATION);
100 return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
103 SETCX(IEEE754_INEXACT);
112 unsigned int ieee754dp_tuns(ieee754dp x)
114 ieee754dp hb = ieee754dp_1e31();
116 /* what if x < 0 ?? */
117 if (ieee754dp_lt(x, hb))
118 return (unsigned) ieee754dp_tint(x);
120 return (unsigned) ieee754dp_tint(ieee754dp_sub(x, hb)) |
121 ((unsigned) 1 << 31);