blob: 4093723d1aa5e89fa79356863819385dc1f7163b [file] [log] [blame]
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
30ieee754sp ieee754sp_fdp(ieee754dp x)
31{
32 COMPXDP;
33 ieee754sp nan;
34
35 EXPLODEXDP;
36
37 CLEARCX;
38
39 FLUSHXDP;
40
41 switch (xc) {
42 case IEEE754_CLASS_SNAN:
43 SETCX(IEEE754_INVALID_OPERATION);
44 return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp");
45 case IEEE754_CLASS_QNAN:
46 nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
47 (xm >> (DP_MBITS - SP_MBITS)));
48 if (!ieee754sp_isnan(nan))
49 nan = ieee754sp_indef();
50 return ieee754sp_nanxcpt(nan, "fdp", x);
51 case IEEE754_CLASS_INF:
52 return ieee754sp_inf(xs);
53 case IEEE754_CLASS_ZERO:
54 return ieee754sp_zero(xs);
55 case IEEE754_CLASS_DNORM:
56 /* can't possibly be sp representable */
57 SETCX(IEEE754_UNDERFLOW);
58 SETCX(IEEE754_INEXACT);
59 if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
60 (ieee754_csr.rm == IEEE754_RD && xs))
61 return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x);
62 return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x);
63 case IEEE754_CLASS_NORM:
64 break;
65 }
66
67 {
68 u32 rm;
69
70 /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift
71 */
72 rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) |
73 ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0);
74
75 SPNORMRET1(xs, xe, rm, "fdp", x);
76 }
77}