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gerrit-public.fairphone.software / kernel / msm / 60c92c79efac8c50fbc72b7f7f0877a29e8ce0cc / . / arch / mips / math-emu / dp_tint.c
blob: 0ebe8598b94ae6ad0f7542d3cd263d874d3c1c73 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]1/* IEEE754 floating point arithmetic
2 * double precision: common utilities
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 "ieee754dp.h"
29
30int ieee754dp_tint(ieee754dp x)
31{
32 COMPXDP;
33
34 CLEARCX;
35
36 EXPLODEXDP;
37 FLUSHXDP;
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(), "dp_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 /* Set invalid. We will only use overflow for floating
53 point overflow */
54 SETCX(IEEE754_INVALID_OPERATION);
55 return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
56 }
57 /* oh gawd */
58 if (xe > DP_MBITS) {
59 xm <<= xe - DP_MBITS;
60 } else if (xe < DP_MBITS) {
61 u64 residue;
62 int round;
63 int sticky;
64 int odd;
65
66 if (xe < -1) {
67 residue = xm;
68 round = 0;
69 sticky = residue != 0;
70 xm = 0;
Andrea Gelmini6337f5e2010-05-23 21:52:06 +0200[diff] [blame]71 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]72 residue = xm << (64 - DP_MBITS + xe);
73 round = (residue >> 63) != 0;
74 sticky = (residue << 1) != 0;
75 xm >>= DP_MBITS - xe;
76 }
77 /* Note: At this point upper 32 bits of xm are guaranteed
78 to be zero */
79 odd = (xm & 0x1) != 0x0;
80 switch (ieee754_csr.rm) {
81 case IEEE754_RN:
82 if (round && (sticky || odd))
83 xm++;
84 break;
85 case IEEE754_RZ:
86 break;
87 case IEEE754_RU: /* toward +Infinity */
88 if ((round || sticky) && !xs)
89 xm++;
90 break;
91 case IEEE754_RD: /* toward -Infinity */
92 if ((round || sticky) && xs)
93 xm++;
94 break;
95 }
96 /* look for valid corner case 0x80000000 */
97 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
98 /* This can happen after rounding */
99 SETCX(IEEE754_INVALID_OPERATION);
100 return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
101 }
102 if (round || sticky)
103 SETCX(IEEE754_INEXACT);
104 }
105 if (xs)
106 return -xm;
107 else
108 return xm;
109}
110
111
112unsigned int ieee754dp_tuns(ieee754dp x)
113{
114 ieee754dp hb = ieee754dp_1e31();
115
116 /* what if x < 0 ?? */
117 if (ieee754dp_lt(x, hb))
118 return (unsigned) ieee754dp_tint(x);
119
120 return (unsigned) ieee754dp_tint(ieee754dp_sub(x, hb)) |
121 ((unsigned) 1 << 31);
122}