blob: e1515aae0166d4653eb395a38555b9b7b0630997 [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.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
8 * ########################################################################
9 *
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.
13 *
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
17 * for more details.
18 *
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.
22 *
23 * ########################################################################
24 */
25
26
27#include "ieee754sp.h"
28
29ieee754sp ieee754sp_fdp(ieee754dp x)
30{
31 COMPXDP;
32 ieee754sp nan;
33
34 EXPLODEXDP;
35
36 CLEARCX;
37
38 FLUSHXDP;
39
40 switch (xc) {
41 case IEEE754_CLASS_SNAN:
42 SETCX(IEEE754_INVALID_OPERATION);
43 return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp");
44 case IEEE754_CLASS_QNAN:
45 nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
46 (xm >> (DP_MBITS - SP_MBITS)));
47 if (!ieee754sp_isnan(nan))
48 nan = ieee754sp_indef();
49 return ieee754sp_nanxcpt(nan, "fdp", x);
50 case IEEE754_CLASS_INF:
51 return ieee754sp_inf(xs);
52 case IEEE754_CLASS_ZERO:
53 return ieee754sp_zero(xs);
54 case IEEE754_CLASS_DNORM:
55 /* can't possibly be sp representable */
56 SETCX(IEEE754_UNDERFLOW);
57 SETCX(IEEE754_INEXACT);
58 if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
59 (ieee754_csr.rm == IEEE754_RD && xs))
60 return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x);
61 return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x);
62 case IEEE754_CLASS_NORM:
63 break;
64 }
65
66 {
67 u32 rm;
68
69 /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift
70 */
71 rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) |
72 ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0);
73
74 SPNORMRET1(xs, xe, rm, "fdp", x);
75 }
76}