1/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 *  This program is free software; you can distribute it and/or modify it
9 *  under the terms of the GNU General Public License (Version 2) as
10 *  published by the Free Software Foundation.
11 *
12 *  This program is distributed in the hope it will be useful, but WITHOUT
13 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 *  for more details.
16 *
17 *  You should have received a copy of the GNU General Public License along
18 *  with this program; if not, write to the Free Software Foundation, Inc.,
19 *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
20 */
21
22#include "ieee754sp.h"
23#include "ieee754dp.h"
24
25static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm)
26{
27	return buildsp(xs, SP_EMAX + 1 + SP_EBIAS,
28		       xm >> (DP_FBITS - SP_FBITS));
29}
30
31union ieee754sp ieee754sp_fdp(union ieee754dp x)
32{
33	union ieee754sp y;
34	u32 rm;
35
36	COMPXDP;
37	COMPYSP;
38
39	EXPLODEXDP;
40
41	ieee754_clearcx();
42
43	FLUSHXDP;
44
45	switch (xc) {
46	case IEEE754_CLASS_SNAN:
47		return ieee754sp_nanxcpt(ieee754sp_nan_fdp(xs, xm));
48
49	case IEEE754_CLASS_QNAN:
50		y = ieee754sp_nan_fdp(xs, xm);
51		EXPLODEYSP;
52		if (!ieee754_class_nan(yc))
53			y = ieee754sp_indef();
54		return y;
55
56	case IEEE754_CLASS_INF:
57		return ieee754sp_inf(xs);
58
59	case IEEE754_CLASS_ZERO:
60		return ieee754sp_zero(xs);
61
62	case IEEE754_CLASS_DNORM:
63		/* can't possibly be sp representable */
64		ieee754_setcx(IEEE754_UNDERFLOW);
65		ieee754_setcx(IEEE754_INEXACT);
66		if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
67				(ieee754_csr.rm == FPU_CSR_RD && xs))
68			return ieee754sp_mind(xs);
69		return ieee754sp_zero(xs);
70
71	case IEEE754_CLASS_NORM:
72		break;
73	}
74
75	/*
76	 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
77	 */
78	rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
79	     ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
80
81	return ieee754sp_format(xs, xe, rm);
82}
83