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/arch/mips/math-emu/sp_fdp.c

https://bitbucket.org/evzijst/gittest
C | 77 lines | 39 code | 10 blank | 28 comment | 8 complexity | 9799fa779b0b83dda8f046f9557edbd2 MD5 | raw file
 1/* 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}