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gerrit-public.fairphone.software / kernel / msm-4.19 / be49b30a98fe7e20f898fcfe7b6c082700fb96e8 / . / arch / mips / math-emu / sp_tint.c
blob: 0fe9acc7716edecdf005be7836bb4544bcca9473 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]1/* 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 -0700[diff] [blame]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 <linux/kernel.h>
28#include "ieee754sp.h"
29
30int ieee754sp_tint(ieee754sp x)
31{
32 COMPXSP;
33
34 CLEARCX;
35
36 EXPLODEXSP;
37 FLUSHXSP;
38
39 switch (xc) {
40 case IEEE754_CLASS_SNAN:
41 case IEEE754_CLASS_QNAN:
42 case IEEE754_CLASS_INF:
43 SETCX(IEEE754_INVALID_OPERATION);
44 return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
45 case IEEE754_CLASS_ZERO:
46 return 0;
47 case IEEE754_CLASS_DNORM:
48 case IEEE754_CLASS_NORM:
49 break;
50 }
51 if (xe >= 31) {
52 /* look for valid corner case */
53 if (xe == 31 && xs && xm == SP_HIDDEN_BIT)
54 return -0x80000000;
55 /* Set invalid. We will only use overflow for floating
56 point overflow */
57 SETCX(IEEE754_INVALID_OPERATION);
58 return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
59 }
60 /* oh gawd */
61 if (xe > SP_MBITS) {
62 xm <<= xe - SP_MBITS;
63 } else {
64 u32 residue;
65 int round;
66 int sticky;
67 int odd;
68
69 if (xe < -1) {
70 residue = xm;
71 round = 0;
72 sticky = residue != 0;
73 xm = 0;
Andrea Gelmini3e4088a2010-05-23 21:52:09 +0200[diff] [blame]74 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]75 /* Shifting a u32 32 times does not work,
76 * so we do it in two steps. Be aware that xe
77 * may be -1 */
78 residue = xm << (xe + 1);
79 residue <<= 31 - SP_MBITS;
80 round = (residue >> 31) != 0;
81 sticky = (residue << 1) != 0;
82 xm >>= SP_MBITS - xe;
83 }
84 odd = (xm & 0x1) != 0x0;
85 switch (ieee754_csr.rm) {
86 case IEEE754_RN:
87 if (round && (sticky || odd))
88 xm++;
89 break;
90 case IEEE754_RZ:
91 break;
92 case IEEE754_RU: /* toward +Infinity */
93 if ((round || sticky) && !xs)
94 xm++;
95 break;
96 case IEEE754_RD: /* toward -Infinity */
97 if ((round || sticky) && xs)
98 xm++;
99 break;
100 }
101 if ((xm >> 31) != 0) {
102 /* This can happen after rounding */
103 SETCX(IEEE754_INVALID_OPERATION);
104 return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
105 }
106 if (round || sticky)
107 SETCX(IEEE754_INEXACT);
108 }
109 if (xs)
110 return -xm;
111 else
112 return xm;
113}
114
115
116unsigned int ieee754sp_tuns(ieee754sp x)
117{
118 ieee754sp hb = ieee754sp_1e31();
119
120 /* what if x < 0 ?? */
121 if (ieee754sp_lt(x, hb))
122 return (unsigned) ieee754sp_tint(x);
123
124 return (unsigned) ieee754sp_tint(ieee754sp_sub(x, hb)) |
125 ((unsigned) 1 << 31);
126}