xref: /openbmc/linux/arch/mips/math-emu/sp_flong.c (revision 12eb4683)
1 /* IEEE754 floating point arithmetic
2  * single precision
3  */
4 /*
5  * MIPS floating point support
6  * Copyright (C) 1994-2000 Algorithmics Ltd.
7  *
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 
29 ieee754sp ieee754sp_flong(s64 x)
30 {
31 	u64 xm;		/* <--- need 64-bit mantissa temp */
32 	int xe;
33 	int xs;
34 
35 	CLEARCX;
36 
37 	if (x == 0)
38 		return ieee754sp_zero(0);
39 	if (x == 1 || x == -1)
40 		return ieee754sp_one(x < 0);
41 	if (x == 10 || x == -10)
42 		return ieee754sp_ten(x < 0);
43 
44 	xs = (x < 0);
45 	if (xs) {
46 		if (x == (1ULL << 63))
47 			xm = (1ULL << 63);	/* max neg can't be safely negated */
48 		else
49 			xm = -x;
50 	} else {
51 		xm = x;
52 	}
53 	xe = SP_MBITS + 3;
54 
55 	if (xm >> (SP_MBITS + 1 + 3)) {
56 		/* shunt out overflow bits
57 		 */
58 		while (xm >> (SP_MBITS + 1 + 3)) {
59 			SPXSRSX1();
60 		}
61 	} else {
62 		/* normalize in grs extended single precision */
63 		while ((xm >> (SP_MBITS + 3)) == 0) {
64 			xm <<= 1;
65 			xe--;
66 		}
67 	}
68 	SPNORMRET1(xs, xe, xm, "sp_flong", x);
69 }
70 
71 
72 ieee754sp ieee754sp_fulong(u64 u)
73 {
74 	if ((s64) u < 0)
75 		return ieee754sp_add(ieee754sp_1e63(),
76 				     ieee754sp_flong(u & ~(1ULL << 63)));
77 	return ieee754sp_flong(u);
78 }
79