xref: /openbmc/linux/arch/mips/math-emu/dp_fsp.c (revision 64c70b1c)
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 
30 ieee754dp 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 }
75