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

https://bitbucket.org/evzijst/gittest
C | 74 lines | 35 code | 10 blank | 29 comment | 3 complexity | fd0a15c2c911b2727f206ce04949458e MD5 | raw file
 1/* IEEE754 floating point arithmetic
 2 * double precision: common utilities
 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 "ieee754dp.h"
29
30ieee754dp ieee754dp_fsp(ieee754sp x)
31{
32	COMPXSP;
33
34	EXPLODEXSP;
35
36	CLEARCX;
37
38	FLUSHXSP;
39
40	switch (xc) {
41	case IEEE754_CLASS_SNAN:
42		SETCX(IEEE754_INVALID_OPERATION);
43		return ieee754dp_nanxcpt(ieee754dp_indef(), "fsp");
44	case IEEE754_CLASS_QNAN:
45		return ieee754dp_nanxcpt(builddp(xs,
46						 DP_EMAX + 1 + DP_EBIAS,
47						 ((u64) xm
48						  << (DP_MBITS -
49						      SP_MBITS))), "fsp",
50					 x);
51	case IEEE754_CLASS_INF:
52		return ieee754dp_inf(xs);
53	case IEEE754_CLASS_ZERO:
54		return ieee754dp_zero(xs);
55	case IEEE754_CLASS_DNORM:
56		/* normalize */
57		while ((xm >> SP_MBITS) == 0) {
58			xm <<= 1;
59			xe--;
60		}
61		break;
62	case IEEE754_CLASS_NORM:
63		break;
64	}
65
66	/* CANT possibly overflow,underflow, or need rounding
67	 */
68
69	/* drop the hidden bit */
70	xm &= ~SP_HIDDEN_BIT;
71
72	return builddp(xs, xe + DP_EBIAS,
73		       (u64) xm << (DP_MBITS - SP_MBITS));
74}