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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 * http://www.algor.co.uk
8 *
9 * ########################################################################
10 *
11 * This program is free software; you can distribute it and/or modify it
12 * under the terms of the GNU General Public License (Version 2) as
13 * published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 * for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
23 *
24 * ########################################################################
25 */
26
27
28#include "ieee754sp.h"
29
30s64 ieee754sp_tlong(ieee754sp x)
31{
32 COMPXDP; /* <-- need 64-bit mantissa tmp */
33
34 CLEARCX;
35
36 EXPLODEXSP;
37 FLUSHXSP;
38
39 switch (xc) {
40 case IEEE754_CLASS_SNAN:
41 case IEEE754_CLASS_QNAN:
42 case IEEE754_CLASS_INF:
43 SETCX(IEEE754_INVALID_OPERATION);
44 return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
45 case IEEE754_CLASS_ZERO:
46 return 0;
47 case IEEE754_CLASS_DNORM:
48 case IEEE754_CLASS_NORM:
49 break;
50 }
51 if (xe >= 63) {
52 /* look for valid corner case */
53 if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
54 return -0x8000000000000000LL;
55 /* Set invalid. We will only use overflow for floating
56 point overflow */
57 SETCX(IEEE754_INVALID_OPERATION);
58 return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
59 }
60 /* oh gawd */
61 if (xe > SP_MBITS) {
62 xm <<= xe - SP_MBITS;
63 } else if (xe < SP_MBITS) {
64 u32 residue;
65 int round;
66 int sticky;
67 int odd;
68
69 if (xe < -1) {
70 residue = xm;
71 round = 0;
72 sticky = residue != 0;
73 xm = 0;
74 }
75 else {
76 residue = xm << (32 - SP_MBITS + xe);
77 round = (residue >> 31) != 0;
78 sticky = (residue << 1) != 0;
79 xm >>= SP_MBITS - xe;
80 }
81 odd = (xm & 0x1) != 0x0;
82 switch (ieee754_csr.rm) {
83 case IEEE754_RN:
84 if (round && (sticky || odd))
85 xm++;
86 break;
87 case IEEE754_RZ:
88 break;
89 case IEEE754_RU: /* toward +Infinity */
90 if ((round || sticky) && !xs)
91 xm++;
92 break;
93 case IEEE754_RD: /* toward -Infinity */
94 if ((round || sticky) && xs)
95 xm++;
96 break;
97 }
98 if ((xm >> 63) != 0) {
99 /* This can happen after rounding */
100 SETCX(IEEE754_INVALID_OPERATION);
101 return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
102 }
103 if (round || sticky)
104 SETCX(IEEE754_INEXACT);
105 }
106 if (xs)
107 return -xm;
108 else
109 return xm;
110}
111
112
113u64 ieee754sp_tulong(ieee754sp x)
114{
115 ieee754sp hb = ieee754sp_1e63();
116
117 /* what if x < 0 ?? */
118 if (ieee754sp_lt(x, hb))
119 return (u64) ieee754sp_tlong(x);
120
121 return (u64) ieee754sp_tlong(ieee754sp_sub(x, hb)) |
122 (1ULL << 63);
123}