1 /* IEEE754 floating point arithmetic
2 * double precision: common utilities
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 "ieee754dp.h"
24 int ieee754dp_tint(union ieee754dp x)
39 case IEEE754_CLASS_SNAN:
40 case IEEE754_CLASS_QNAN:
41 case IEEE754_CLASS_INF:
42 ieee754_setcx(IEEE754_INVALID_OPERATION);
43 return ieee754si_indef();
45 case IEEE754_CLASS_ZERO:
48 case IEEE754_CLASS_DNORM:
49 case IEEE754_CLASS_NORM:
53 /* Set invalid. We will only use overflow for floating
55 ieee754_setcx(IEEE754_INVALID_OPERATION);
56 return ieee754si_indef();
61 } else if (xe < DP_FBITS) {
65 sticky = residue != 0;
68 residue = xm << (64 - DP_FBITS + xe);
69 round = (residue >> 63) != 0;
70 sticky = (residue << 1) != 0;
73 /* Note: At this point upper 32 bits of xm are guaranteed
75 odd = (xm & 0x1) != 0x0;
76 switch (ieee754_csr.rm) {
78 if (round && (sticky || odd))
83 case FPU_CSR_RU: /* toward +Infinity */
84 if ((round || sticky) && !xs)
87 case FPU_CSR_RD: /* toward -Infinity */
88 if ((round || sticky) && xs)
92 /* look for valid corner case 0x80000000 */
93 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
94 /* This can happen after rounding */
95 ieee754_setcx(IEEE754_INVALID_OPERATION);
96 return ieee754si_indef();
99 ieee754_setcx(IEEE754_INEXACT);