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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
12s64 ieee754dp_tlong(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 ieee754di_indef();
31
32 case IEEE754_CLASS_INF:
33 ieee754_setcx(IEEE754_INVALID_OPERATION);
34 return ieee754di_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 >= 63) {
44 /* look for valid corner case */
45 if (xe == 63 && xs && xm == DP_HIDDEN_BIT)
46 return -0x8000000000000000LL;
47 /* Set invalid. We will only use overflow for floating
48 point overflow */
49 ieee754_setcx(IEEE754_INVALID_OPERATION);
50 return ieee754di_overflow(xs);
51 }
52 /* oh gawd */
53 if (xe > DP_FBITS) {
54 xm <<= xe - DP_FBITS;
55 } else if (xe < DP_FBITS) {
56 if (xe < -1) {
57 residue = xm;
58 round = 0;
59 sticky = residue != 0;
60 xm = 0;
61 } else {
62 /* Shifting a u64 64 times does not work,
63 * so we do it in two steps. Be aware that xe
64 * may be -1 */
65 residue = xm << (xe + 1);
66 residue <<= 63 - DP_FBITS;
67 round = (residue >> 63) != 0;
68 sticky = (residue << 1) != 0;
69 xm >>= DP_FBITS - xe;
70 }
71 odd = (xm & 0x1) != 0x0;
72 switch (ieee754_csr.rm) {
73 case FPU_CSR_RN:
74 if (round && (sticky || odd))
75 xm++;
76 break;
77 case FPU_CSR_RZ:
78 break;
79 case FPU_CSR_RU: /* toward +Infinity */
80 if ((round || sticky) && !xs)
81 xm++;
82 break;
83 case FPU_CSR_RD: /* toward -Infinity */
84 if ((round || sticky) && xs)
85 xm++;
86 break;
87 }
88 if ((xm >> 63) != 0) {
89 /* This can happen after rounding */
90 ieee754_setcx(IEEE754_INVALID_OPERATION);
91 return ieee754di_overflow(xs);
92 }
93 if (round || sticky)
94 ieee754_setcx(IEEE754_INEXACT);
95 }
96 if (xs)
97 return -xm;
98 else
99 return xm;
100}
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
24s64 ieee754dp_tlong(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 ieee754di_indef();
43
44 case IEEE754_CLASS_INF:
45 ieee754_setcx(IEEE754_INVALID_OPERATION);
46 return ieee754di_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 >= 63) {
56 /* look for valid corner case */
57 if (xe == 63 && xs && xm == DP_HIDDEN_BIT)
58 return -0x8000000000000000LL;
59 /* Set invalid. We will only use overflow for floating
60 point overflow */
61 ieee754_setcx(IEEE754_INVALID_OPERATION);
62 return ieee754di_overflow(xs);
63 }
64 /* oh gawd */
65 if (xe > DP_FBITS) {
66 xm <<= xe - DP_FBITS;
67 } else if (xe < DP_FBITS) {
68 if (xe < -1) {
69 residue = xm;
70 round = 0;
71 sticky = residue != 0;
72 xm = 0;
73 } else {
74 /* Shifting a u64 64 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 <<= 63 - DP_FBITS;
79 round = (residue >> 63) != 0;
80 sticky = (residue << 1) != 0;
81 xm >>= DP_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 >> 63) != 0) {
101 /* This can happen after rounding */
102 ieee754_setcx(IEEE754_INVALID_OPERATION);
103 return ieee754di_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}