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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * 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.,
Ralf Baechle3f7cac42014-04-26 01:49:14 +020019 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 */
21
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include "ieee754sp.h"
Ralf Baechleb3a7ad22014-04-22 16:33:07 +020023#include "ieee754dp.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Maciej W. Rozyckid19cf862015-04-03 23:25:23 +010025static 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
Ralf Baechle2209bcb2014-04-16 01:31:11 +020031union ieee754sp ieee754sp_fdp(union ieee754dp x)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
Maciej W. Rozyckib0c2f8f2015-04-03 23:25:52 +010033 union ieee754sp y;
Ralf Baechle3f7cac42014-04-26 01:49:14 +020034 u32 rm;
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 COMPXDP;
Maciej W. Rozyckib0c2f8f2015-04-03 23:25:52 +010037 COMPYSP;
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39 EXPLODEXDP;
40
Ralf Baechle9e8bad12014-04-19 00:36:32 +020041 ieee754_clearcx();
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43 FLUSHXDP;
44
45 switch (xc) {
46 case IEEE754_CLASS_SNAN:
Maciej W. Rozycki90d53a92015-11-13 00:47:28 +000047 x = ieee754dp_nanxcpt(x);
48 EXPLODEXDP;
49 /* Fall through. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 case IEEE754_CLASS_QNAN:
Maciej W. Rozyckib0c2f8f2015-04-03 23:25:52 +010051 y = ieee754sp_nan_fdp(xs, xm);
Maciej W. Rozycki90d53a92015-11-13 00:47:28 +000052 if (!ieee754_csr.nan2008) {
53 EXPLODEYSP;
54 if (!ieee754_class_nan(yc))
55 y = ieee754sp_indef();
56 }
Maciej W. Rozyckib0c2f8f2015-04-03 23:25:52 +010057 return y;
Ralf Baechle3f7cac42014-04-26 01:49:14 +020058
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 case IEEE754_CLASS_INF:
60 return ieee754sp_inf(xs);
Ralf Baechle3f7cac42014-04-26 01:49:14 +020061
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 case IEEE754_CLASS_ZERO:
63 return ieee754sp_zero(xs);
Ralf Baechle3f7cac42014-04-26 01:49:14 +020064
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 case IEEE754_CLASS_DNORM:
66 /* can't possibly be sp representable */
Ralf Baechle9e8bad12014-04-19 00:36:32 +020067 ieee754_setcx(IEEE754_UNDERFLOW);
68 ieee754_setcx(IEEE754_INEXACT);
Ralf Baechle56a64732014-04-30 11:21:55 +020069 if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
70 (ieee754_csr.rm == FPU_CSR_RD && xs))
Ralf Baechle90efba32014-04-25 03:19:57 +020071 return ieee754sp_mind(xs);
72 return ieee754sp_zero(xs);
Ralf Baechle3f7cac42014-04-26 01:49:14 +020073
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 case IEEE754_CLASS_NORM:
75 break;
76 }
77
Ralf Baechle3f7cac42014-04-26 01:49:14 +020078 /*
79 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
80 */
81 rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
82 ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
Ralf Baechle3f7cac42014-04-26 01:49:14 +020084 return ieee754sp_format(xs, xe, rm);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085}