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 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 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 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 44 uint64_t clmul_8x4_odd(uint64_t n, uint64_t m) 45 { 46 return clmul_8x4_even(n >> 8, m >> 8); 47 } 48 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 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 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 78 uint64_t clmul_16x2_odd(uint64_t n, uint64_t m) 79 { 80 return clmul_16x2_even(n >> 16, m >> 16); 81 } 82 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 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