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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
Ralf Baechle2209bcb2014-04-16 01:31:11 +020025s64 ieee754sp_tlong(union ieee754sp x)
Linus Torvalds1da177e2005-04-16 15:20:36 -070026{
Ralf Baechle3f7cac42014-04-26 01:49:14 +020027 u32 residue;
28 int round;
29 int sticky;
30 int odd;
31
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 COMPXDP; /* <-- need 64-bit mantissa tmp */
33
Ralf Baechle9e8bad12014-04-19 00:36:32 +020034 ieee754_clearcx();
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36 EXPLODEXSP;
37 FLUSHXSP;
38
39 switch (xc) {
40 case IEEE754_CLASS_SNAN:
41 case IEEE754_CLASS_QNAN:
Ralf Baechle9e8bad12014-04-19 00:36:32 +020042 ieee754_setcx(IEEE754_INVALID_OPERATION);
Ralf Baechle90efba32014-04-25 03:19:57 +020043 return ieee754di_indef();
Ralf Baechle3f7cac42014-04-26 01:49:14 +020044
Maciej W. Rozycki90d53a92015-11-13 00:47:28 +000045 case IEEE754_CLASS_INF:
46 ieee754_setcx(IEEE754_INVALID_OPERATION);
47 return ieee754di_overflow(xs);
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 case IEEE754_CLASS_ZERO:
50 return 0;
Ralf Baechle3f7cac42014-04-26 01:49:14 +020051
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 case IEEE754_CLASS_DNORM:
53 case IEEE754_CLASS_NORM:
54 break;
55 }
56 if (xe >= 63) {
57 /* look for valid corner case */
58 if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
59 return -0x8000000000000000LL;
60 /* Set invalid. We will only use overflow for floating
61 point overflow */
Ralf Baechle9e8bad12014-04-19 00:36:32 +020062 ieee754_setcx(IEEE754_INVALID_OPERATION);
Maciej W. Rozycki90d53a92015-11-13 00:47:28 +000063 return ieee754di_overflow(xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 }
65 /* oh gawd */
Ralf Baechlead8fb552014-04-22 15:51:55 +020066 if (xe > SP_FBITS) {
67 xm <<= xe - SP_FBITS;
68 } else if (xe < SP_FBITS) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 if (xe < -1) {
70 residue = xm;
71 round = 0;
72 sticky = residue != 0;
73 xm = 0;
Andrea Gelminiabb86dc2010-05-23 21:52:10 +020074 } else {
Ralf Baechlead8fb552014-04-22 15:51:55 +020075 residue = xm << (32 - SP_FBITS + xe);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 round = (residue >> 31) != 0;
77 sticky = (residue << 1) != 0;
Ralf Baechlead8fb552014-04-22 15:51:55 +020078 xm >>= SP_FBITS - xe;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 }
80 odd = (xm & 0x1) != 0x0;
81 switch (ieee754_csr.rm) {
Ralf Baechle56a64732014-04-30 11:21:55 +020082 case FPU_CSR_RN:
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 if (round && (sticky || odd))
84 xm++;
85 break;
Ralf Baechle56a64732014-04-30 11:21:55 +020086 case FPU_CSR_RZ:
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 break;
Ralf Baechle56a64732014-04-30 11:21:55 +020088 case FPU_CSR_RU: /* toward +Infinity */
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 if ((round || sticky) && !xs)
90 xm++;
91 break;
Ralf Baechle56a64732014-04-30 11:21:55 +020092 case FPU_CSR_RD: /* toward -Infinity */
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 if ((round || sticky) && xs)
94 xm++;
95 break;
96 }
97 if ((xm >> 63) != 0) {
98 /* This can happen after rounding */
Ralf Baechle9e8bad12014-04-19 00:36:32 +020099 ieee754_setcx(IEEE754_INVALID_OPERATION);
Maciej W. Rozycki90d53a92015-11-13 00:47:28 +0000100 return ieee754di_overflow(xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 }
102 if (round || sticky)
Ralf Baechle9e8bad12014-04-19 00:36:32 +0200103 ieee754_setcx(IEEE754_INEXACT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 }
105 if (xs)
106 return -xm;
107 else
108 return xm;
109}