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1/* IEEE754 floating point arithmetic
2 * double precision: common utilities
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 "ieee754dp.h"
23
24int ieee754dp_tint(union ieee754dp x)
25{
26 u64 residue;
27 int round;
28 int sticky;
29 int odd;
30
31 COMPXDP;
32
33 ieee754_clearcx();
34
35 EXPLODEXDP;
36 FLUSHXDP;
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 /* Set invalid. We will only use overflow for floating
57 point overflow */
58 ieee754_setcx(IEEE754_INVALID_OPERATION);
59 return ieee754si_overflow(xs);
60 }
61 /* oh gawd */
62 if (xe > DP_FBITS) {
63 xm <<= xe - DP_FBITS;
64 } else if (xe < DP_FBITS) {
65 if (xe < -1) {
66 residue = xm;
67 round = 0;
68 sticky = residue != 0;
69 xm = 0;
70 } else {
71 residue = xm << (64 - DP_FBITS + xe);
72 round = (residue >> 63) != 0;
73 sticky = (residue << 1) != 0;
74 xm >>= DP_FBITS - xe;
75 }
76 /* Note: At this point upper 32 bits of xm are guaranteed
77 to be zero */
78 odd = (xm & 0x1) != 0x0;
79 switch (ieee754_csr.rm) {
80 case FPU_CSR_RN:
81 if (round && (sticky || odd))
82 xm++;
83 break;
84 case FPU_CSR_RZ:
85 break;
86 case FPU_CSR_RU: /* toward +Infinity */
87 if ((round || sticky) && !xs)
88 xm++;
89 break;
90 case FPU_CSR_RD: /* toward -Infinity */
91 if ((round || sticky) && xs)
92 xm++;
93 break;
94 }
95 /* look for valid corner case 0x80000000 */
96 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
97 /* This can happen after rounding */
98 ieee754_setcx(IEEE754_INVALID_OPERATION);
99 return ieee754si_overflow(xs);
100 }
101 if (round || sticky)
102 ieee754_setcx(IEEE754_INEXACT);
103 }
104 if (xs)
105 return -xm;
106 else
107 return xm;
108}
1// SPDX-License-Identifier: GPL-2.0-only
2/* IEEE754 floating point arithmetic
3 * double precision: common utilities
4 */
5/*
6 * MIPS floating point support
7 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 */
9
10#include "ieee754dp.h"
11
12int ieee754dp_tint(union ieee754dp x)
13{
14 u64 residue;
15 int round;
16 int sticky;
17 int odd;
18
19 COMPXDP;
20
21 ieee754_clearcx();
22
23 EXPLODEXDP;
24 FLUSHXDP;
25
26 switch (xc) {
27 case IEEE754_CLASS_SNAN:
28 case IEEE754_CLASS_QNAN:
29 ieee754_setcx(IEEE754_INVALID_OPERATION);
30 return ieee754si_indef();
31
32 case IEEE754_CLASS_INF:
33 ieee754_setcx(IEEE754_INVALID_OPERATION);
34 return ieee754si_overflow(xs);
35
36 case IEEE754_CLASS_ZERO:
37 return 0;
38
39 case IEEE754_CLASS_DNORM:
40 case IEEE754_CLASS_NORM:
41 break;
42 }
43 if (xe > 31) {
44 /* Set invalid. We will only use overflow for floating
45 point overflow */
46 ieee754_setcx(IEEE754_INVALID_OPERATION);
47 return ieee754si_overflow(xs);
48 }
49 /* oh gawd */
50 if (xe > DP_FBITS) {
51 xm <<= xe - DP_FBITS;
52 } else if (xe < DP_FBITS) {
53 if (xe < -1) {
54 residue = xm;
55 round = 0;
56 sticky = residue != 0;
57 xm = 0;
58 } else {
59 residue = xm << (64 - DP_FBITS + xe);
60 round = (residue >> 63) != 0;
61 sticky = (residue << 1) != 0;
62 xm >>= DP_FBITS - xe;
63 }
64 /* Note: At this point upper 32 bits of xm are guaranteed
65 to be zero */
66 odd = (xm & 0x1) != 0x0;
67 switch (ieee754_csr.rm) {
68 case FPU_CSR_RN:
69 if (round && (sticky || odd))
70 xm++;
71 break;
72 case FPU_CSR_RZ:
73 break;
74 case FPU_CSR_RU: /* toward +Infinity */
75 if ((round || sticky) && !xs)
76 xm++;
77 break;
78 case FPU_CSR_RD: /* toward -Infinity */
79 if ((round || sticky) && xs)
80 xm++;
81 break;
82 }
83 /* look for valid corner case 0x80000000 */
84 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
85 /* This can happen after rounding */
86 ieee754_setcx(IEEE754_INVALID_OPERATION);
87 return ieee754si_overflow(xs);
88 }
89 if (round || sticky)
90 ieee754_setcx(IEEE754_INEXACT);
91 }
92 if (xs)
93 return -xm;
94 else
95 return xm;
96}