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1/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
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;
74 } else {
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}
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
24int ieee754sp_tint(union ieee754sp x)
25{
26 u32 residue;
27 int round;
28 int sticky;
29 int odd;
30
31 COMPXSP;
32
33 ieee754_clearcx();
34
35 EXPLODEXSP;
36 FLUSHXSP;
37
38 switch (xc) {
39 case IEEE754_CLASS_SNAN:
40 case IEEE754_CLASS_QNAN:
41 ieee754_setcx(IEEE754_INVALID_OPERATION);
42 return ieee754si_indef();
43
44 case IEEE754_CLASS_INF:
45 ieee754_setcx(IEEE754_INVALID_OPERATION);
46 return ieee754si_overflow(xs);
47
48 case IEEE754_CLASS_ZERO:
49 return 0;
50
51 case IEEE754_CLASS_DNORM:
52 case IEEE754_CLASS_NORM:
53 break;
54 }
55 if (xe >= 31) {
56 /* look for valid corner case */
57 if (xe == 31 && xs && xm == SP_HIDDEN_BIT)
58 return -0x80000000;
59 /* Set invalid. We will only use overflow for floating
60 point overflow */
61 ieee754_setcx(IEEE754_INVALID_OPERATION);
62 return ieee754si_overflow(xs);
63 }
64 /* oh gawd */
65 if (xe > SP_FBITS) {
66 xm <<= xe - SP_FBITS;
67 } else {
68 if (xe < -1) {
69 residue = xm;
70 round = 0;
71 sticky = residue != 0;
72 xm = 0;
73 } else {
74 /* Shifting a u32 32 times does not work,
75 * so we do it in two steps. Be aware that xe
76 * may be -1 */
77 residue = xm << (xe + 1);
78 residue <<= 31 - SP_FBITS;
79 round = (residue >> 31) != 0;
80 sticky = (residue << 1) != 0;
81 xm >>= SP_FBITS - xe;
82 }
83 odd = (xm & 0x1) != 0x0;
84 switch (ieee754_csr.rm) {
85 case FPU_CSR_RN:
86 if (round && (sticky || odd))
87 xm++;
88 break;
89 case FPU_CSR_RZ:
90 break;
91 case FPU_CSR_RU: /* toward +Infinity */
92 if ((round || sticky) && !xs)
93 xm++;
94 break;
95 case FPU_CSR_RD: /* toward -Infinity */
96 if ((round || sticky) && xs)
97 xm++;
98 break;
99 }
100 if ((xm >> 31) != 0) {
101 /* This can happen after rounding */
102 ieee754_setcx(IEEE754_INVALID_OPERATION);
103 return ieee754si_overflow(xs);
104 }
105 if (round || sticky)
106 ieee754_setcx(IEEE754_INEXACT);
107 }
108 if (xs)
109 return -xm;
110 else
111 return xm;
112}