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 "ieee754dp.h"
29 s64 ieee754dp_tlong(ieee754dp x)
39 case IEEE754_CLASS_SNAN:
40 case IEEE754_CLASS_QNAN:
41 case IEEE754_CLASS_INF:
42 SETCX(IEEE754_INVALID_OPERATION);
43 return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
44 case IEEE754_CLASS_ZERO:
46 case IEEE754_CLASS_DNORM:
47 case IEEE754_CLASS_NORM:
51 /* look for valid corner case */
52 if (xe == 63 && xs && xm == DP_HIDDEN_BIT)
53 return -0x8000000000000000LL;
54 /* Set invalid. We will only use overflow for floating
56 SETCX(IEEE754_INVALID_OPERATION);
57 return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
62 } else if (xe < DP_MBITS) {
71 sticky = residue != 0;
74 /* Shifting a u64 64 times does not work,
75 * so we do it in two steps. Be aware that xe
77 residue = xm << (xe + 1);
78 residue <<= 63 - DP_MBITS;
79 round = (residue >> 63) != 0;
80 sticky = (residue << 1) != 0;
83 odd = (xm & 0x1) != 0x0;
84 switch (ieee754_csr.rm) {
86 if (round && (sticky || odd))
91 case IEEE754_RU: /* toward +Infinity */
92 if ((round || sticky) && !xs)
95 case IEEE754_RD: /* toward -Infinity */
96 if ((round || sticky) && xs)
100 if ((xm >> 63) != 0) {
101 /* This can happen after rounding */
102 SETCX(IEEE754_INVALID_OPERATION);
103 return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
106 SETCX(IEEE754_INEXACT);
115 u64 ieee754dp_tulong(ieee754dp x)
117 ieee754dp hb = ieee754dp_1e63();
119 /* what if x < 0 ?? */
120 if (ieee754dp_lt(x, hb))
121 return (u64) ieee754dp_tlong(x);
123 return (u64) ieee754dp_tlong(ieee754dp_sub(x, hb)) |