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
ieee754sp_nan_fdp(int xs,u64 xm)25 static 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
ieee754sp_fdp(union ieee754dp x)31 union 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 x = ieee754dp_nanxcpt(x);
48 EXPLODEXDP;
49 /* fall through */
50
51 case IEEE754_CLASS_QNAN:
52 y = ieee754sp_nan_fdp(xs, xm);
53 if (!ieee754_csr.nan2008) {
54 EXPLODEYSP;
55 if (!ieee754_class_nan(yc))
56 y = ieee754sp_indef();
57 }
58 return y;
59
60 case IEEE754_CLASS_INF:
61 return ieee754sp_inf(xs);
62
63 case IEEE754_CLASS_ZERO:
64 return ieee754sp_zero(xs);
65
66 case IEEE754_CLASS_DNORM:
67 /* can't possibly be sp representable */
68 ieee754_setcx(IEEE754_UNDERFLOW);
69 ieee754_setcx(IEEE754_INEXACT);
70 if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
71 (ieee754_csr.rm == FPU_CSR_RD && xs))
72 return ieee754sp_mind(xs);
73 return ieee754sp_zero(xs);
74
75 case IEEE754_CLASS_NORM:
76 break;
77 }
78
79 /*
80 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
81 */
82 rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
83 ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
84
85 return ieee754sp_format(xs, xe, rm);
86 }
87