xref: /openbmc/qemu/target/riscv/bitmanip_helper.c (revision d0bf492f)
1 /*
2  * RISC-V Bitmanip Extension Helpers for QEMU.
3  *
4  * Copyright (c) 2020 Kito Cheng, kito.cheng@sifive.com
5  * Copyright (c) 2020 Frank Chang, frank.chang@sifive.com
6  * Copyright (c) 2021 Philipp Tomsich, philipp.tomsich@vrull.eu
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2 or later, as 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 for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program.  If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu/osdep.h"
22 #include "qemu/host-utils.h"
23 #include "exec/exec-all.h"
24 #include "exec/helper-proto.h"
25 #include "tcg/tcg.h"
26 
27 target_ulong HELPER(clmul)(target_ulong rs1, target_ulong rs2)
28 {
29     target_ulong result = 0;
30 
31     for (int i = 0; i < TARGET_LONG_BITS; i++) {
32         if ((rs2 >> i) & 1) {
33             result ^= (rs1 << i);
34         }
35     }
36 
37     return result;
38 }
39 
40 target_ulong HELPER(clmulr)(target_ulong rs1, target_ulong rs2)
41 {
42     target_ulong result = 0;
43 
44     for (int i = 0; i < TARGET_LONG_BITS; i++) {
45         if ((rs2 >> i) & 1) {
46             result ^= (rs1 >> (TARGET_LONG_BITS - i - 1));
47         }
48     }
49 
50     return result;
51 }
52 
53 static inline target_ulong do_swap(target_ulong x, uint64_t mask, int shift)
54 {
55     return ((x & mask) << shift) | ((x & ~mask) >> shift);
56 }
57 
58 target_ulong HELPER(brev8)(target_ulong rs1)
59 {
60     target_ulong x = rs1;
61 
62     x = do_swap(x, 0x5555555555555555ull, 1);
63     x = do_swap(x, 0x3333333333333333ull, 2);
64     x = do_swap(x, 0x0f0f0f0f0f0f0f0full, 4);
65     return x;
66 }
67 
68 static const uint64_t shuf_masks[] = {
69     dup_const(MO_8, 0x44),
70     dup_const(MO_8, 0x30),
71     dup_const(MO_16, 0x0f00),
72     dup_const(MO_32, 0xff0000)
73 };
74 
75 static inline target_ulong do_shuf_stage(target_ulong src, uint64_t maskL,
76                                          uint64_t maskR, int shift)
77 {
78     target_ulong x = src & ~(maskL | maskR);
79 
80     x |= ((src << shift) & maskL) | ((src >> shift) & maskR);
81     return x;
82 }
83 
84 target_ulong HELPER(unzip)(target_ulong rs1)
85 {
86     target_ulong x = rs1;
87 
88     x = do_shuf_stage(x, shuf_masks[0], shuf_masks[0] >> 1, 1);
89     x = do_shuf_stage(x, shuf_masks[1], shuf_masks[1] >> 2, 2);
90     x = do_shuf_stage(x, shuf_masks[2], shuf_masks[2] >> 4, 4);
91     x = do_shuf_stage(x, shuf_masks[3], shuf_masks[3] >> 8, 8);
92     return x;
93 }
94 
95 target_ulong HELPER(zip)(target_ulong rs1)
96 {
97     target_ulong x = rs1;
98 
99     x = do_shuf_stage(x, shuf_masks[3], shuf_masks[3] >> 8, 8);
100     x = do_shuf_stage(x, shuf_masks[2], shuf_masks[2] >> 4, 4);
101     x = do_shuf_stage(x, shuf_masks[1], shuf_masks[1] >> 2, 2);
102     x = do_shuf_stage(x, shuf_masks[0], shuf_masks[0] >> 1, 1);
103     return x;
104 }
105 
106 static inline target_ulong do_xperm(target_ulong rs1, target_ulong rs2,
107                                     uint32_t sz_log2)
108 {
109     target_ulong r = 0;
110     target_ulong sz = 1LL << sz_log2;
111     target_ulong mask = (1LL << sz) - 1;
112     target_ulong pos;
113 
114     for (int i = 0; i < TARGET_LONG_BITS; i += sz) {
115         pos = ((rs2 >> i) & mask) << sz_log2;
116         if (pos < sizeof(target_ulong) * 8) {
117             r |= ((rs1 >> pos) & mask) << i;
118         }
119     }
120     return r;
121 }
122 
123 target_ulong HELPER(xperm4)(target_ulong rs1, target_ulong rs2)
124 {
125     return do_xperm(rs1, rs2, 2);
126 }
127 
128 target_ulong HELPER(xperm8)(target_ulong rs1, target_ulong rs2)
129 {
130     return do_xperm(rs1, rs2, 3);
131 }
132