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 int ieee754sp_tint(union ieee754sp 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 /* look for valid corner case */
54 if (xe == 31 && xs && xm == SP_HIDDEN_BIT)
56 /* Set invalid. We will only use overflow for floating
58 ieee754_setcx(IEEE754_INVALID_OPERATION);
59 return ieee754si_indef();
68 sticky = residue != 0;
71 /* Shifting a u32 32 times does not work,
72 * so we do it in two steps. Be aware that xe
74 residue = xm << (xe + 1);
75 residue <<= 31 - SP_FBITS;
76 round = (residue >> 31) != 0;
77 sticky = (residue << 1) != 0;
80 odd = (xm & 0x1) != 0x0;
81 switch (ieee754_csr.rm) {
83 if (round && (sticky || odd))
88 case FPU_CSR_RU: /* toward +Infinity */
89 if ((round || sticky) && !xs)
92 case FPU_CSR_RD: /* toward -Infinity */
93 if ((round || sticky) && xs)
97 if ((xm >> 31) != 0) {
98 /* This can happen after rounding */
99 ieee754_setcx(IEEE754_INVALID_OPERATION);
100 return ieee754si_indef();
103 ieee754_setcx(IEEE754_INEXACT);