1 /*
2 * Carry-less multiply operations.
3 * SPDX-License-Identifier: GPL-2.0-or-later
4 *
5 * Copyright (C) 2023 Linaro, Ltd.
6 */
7
8 #include "qemu/osdep.h"
9 #include "crypto/clmul.h"
10
clmul_8x8_low(uint64_t n,uint64_t m)11 uint64_t clmul_8x8_low(uint64_t n, uint64_t m)
12 {
13 uint64_t r = 0;
14
15 for (int i = 0; i < 8; ++i) {
16 uint64_t mask = (n & 0x0101010101010101ull) * 0xff;
17 r ^= m & mask;
18 m = (m << 1) & 0xfefefefefefefefeull;
19 n >>= 1;
20 }
21 return r;
22 }
23
clmul_8x4_even_int(uint64_t n,uint64_t m)24 static uint64_t clmul_8x4_even_int(uint64_t n, uint64_t m)
25 {
26 uint64_t r = 0;
27
28 for (int i = 0; i < 8; ++i) {
29 uint64_t mask = (n & 0x0001000100010001ull) * 0xffff;
30 r ^= m & mask;
31 n >>= 1;
32 m <<= 1;
33 }
34 return r;
35 }
36
clmul_8x4_even(uint64_t n,uint64_t m)37 uint64_t clmul_8x4_even(uint64_t n, uint64_t m)
38 {
39 n &= 0x00ff00ff00ff00ffull;
40 m &= 0x00ff00ff00ff00ffull;
41 return clmul_8x4_even_int(n, m);
42 }
43
clmul_8x4_odd(uint64_t n,uint64_t m)44 uint64_t clmul_8x4_odd(uint64_t n, uint64_t m)
45 {
46 return clmul_8x4_even(n >> 8, m >> 8);
47 }
48
unpack_8_to_16(uint64_t x)49 static uint64_t unpack_8_to_16(uint64_t x)
50 {
51 return (x & 0x000000ff)
52 | ((x & 0x0000ff00) << 8)
53 | ((x & 0x00ff0000) << 16)
54 | ((x & 0xff000000) << 24);
55 }
56
clmul_8x4_packed(uint32_t n,uint32_t m)57 uint64_t clmul_8x4_packed(uint32_t n, uint32_t m)
58 {
59 return clmul_8x4_even_int(unpack_8_to_16(n), unpack_8_to_16(m));
60 }
61
clmul_16x2_even(uint64_t n,uint64_t m)62 uint64_t clmul_16x2_even(uint64_t n, uint64_t m)
63 {
64 uint64_t r = 0;
65
66 n &= 0x0000ffff0000ffffull;
67 m &= 0x0000ffff0000ffffull;
68
69 for (int i = 0; i < 16; ++i) {
70 uint64_t mask = (n & 0x0000000100000001ull) * 0xffffffffull;
71 r ^= m & mask;
72 n >>= 1;
73 m <<= 1;
74 }
75 return r;
76 }
77
clmul_16x2_odd(uint64_t n,uint64_t m)78 uint64_t clmul_16x2_odd(uint64_t n, uint64_t m)
79 {
80 return clmul_16x2_even(n >> 16, m >> 16);
81 }
82
clmul_32(uint32_t n,uint32_t m32)83 uint64_t clmul_32(uint32_t n, uint32_t m32)
84 {
85 uint64_t r = 0;
86 uint64_t m = m32;
87
88 for (int i = 0; i < 32; ++i) {
89 r ^= n & 1 ? m : 0;
90 n >>= 1;
91 m <<= 1;
92 }
93 return r;
94 }
95
clmul_64_gen(uint64_t n,uint64_t m)96 Int128 clmul_64_gen(uint64_t n, uint64_t m)
97 {
98 uint64_t rl = 0, rh = 0;
99
100 /* Bit 0 can only influence the low 64-bit result. */
101 if (n & 1) {
102 rl = m;
103 }
104
105 for (int i = 1; i < 64; ++i) {
106 uint64_t mask = -((n >> i) & 1);
107 rl ^= (m << i) & mask;
108 rh ^= (m >> (64 - i)) & mask;
109 }
110 return int128_make128(rl, rh);
111 }
112