xref: /linux/arch/mips/math-emu/sp_fint.c (revision 4854c7b27f0975a2b629f35ea3996d2968eb7c4f)
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 
30 ieee754sp ieee754sp_fint(int x)
31 {
32 	unsigned xm;
33 	int xe;
34 	int xs;
35 
36 	CLEARCX;
37 
38 	if (x == 0)
39 		return ieee754sp_zero(0);
40 	if (x == 1 || x == -1)
41 		return ieee754sp_one(x < 0);
42 	if (x == 10 || x == -10)
43 		return ieee754sp_ten(x < 0);
44 
45 	xs = (x < 0);
46 	if (xs) {
47 		if (x == (1 << 31))
48 			xm = ((unsigned) 1 << 31);	/* max neg can't be safely negated */
49 		else
50 			xm = -x;
51 	} else {
52 		xm = x;
53 	}
54 	xe = SP_MBITS + 3;
55 
56 	if (xm >> (SP_MBITS + 1 + 3)) {
57 		/* shunt out overflow bits
58 		 */
59 		while (xm >> (SP_MBITS + 1 + 3)) {
60 			SPXSRSX1();
61 		}
62 	} else {
63 		/* normalize in grs extended single precision
64 		 */
65 		while ((xm >> (SP_MBITS + 3)) == 0) {
66 			xm <<= 1;
67 			xe--;
68 		}
69 	}
70 	SPNORMRET1(xs, xe, xm, "fint", x);
71 }
72 
73 
74 ieee754sp ieee754sp_funs(unsigned int u)
75 {
76 	if ((int) u < 0)
77 		return ieee754sp_add(ieee754sp_1e31(),
78 				     ieee754sp_fint(u & ~(1 << 31)));
79 	return ieee754sp_fint(u);
80 }
81