1 /*
2 This file is for the Gao-Mateer FFT
3 sse http://www.math.clemson.edu/~sgao/papers/GM10.pdf
4 */
5
6 #include "fft.h"
7
8 #include "vec.h"
9
10 /* input: in, polynomial in bitsliced form */
11 /* output: in, result of applying the radix conversions on in */
radix_conversions(uint64_t * in)12 static void radix_conversions(uint64_t *in) {
13 int i, j, k;
14
15 const uint64_t mask[5][2] = {
16 {0x8888888888888888, 0x4444444444444444},
17 {0xC0C0C0C0C0C0C0C0, 0x3030303030303030},
18 {0xF000F000F000F000, 0x0F000F000F000F00},
19 {0xFF000000FF000000, 0x00FF000000FF0000},
20 {0xFFFF000000000000, 0x0000FFFF00000000}
21 };
22
23 const uint64_t s[5][GFBITS] = {
24 #include "scalars.inc"
25 };
26
27 //
28
29 for (j = 0; j <= 4; j++) {
30 for (i = 0; i < GFBITS; i++) {
31 for (k = 4; k >= j; k--) {
32 in[i] ^= (in[i] & mask[k][0]) >> (1 << k);
33 in[i] ^= (in[i] & mask[k][1]) >> (1 << k);
34 }
35 }
36
37 PQCLEAN_MCELIECE348864F_AVX_vec_mul(in, in, s[j]); // scaling
38 }
39 }
40
41 /* input: in, result of applying the radix conversions to the input polynomial */
42 /* output: out, evaluation results (by applying the FFT butterflies) */
butterflies(vec256 out[][GFBITS],const uint64_t * in)43 static void butterflies(vec256 out[][ GFBITS ], const uint64_t *in) {
44 int i, j, k, s, b;
45
46 uint64_t t0, t1, t2, t3;
47
48 const vec256 consts[ 17 ][ GFBITS ] = {
49 #include "consts.inc"
50 };
51
52 uint64_t consts_ptr = 0;
53
54 const unsigned char reversal[64] = {
55 0, 32, 16, 48, 8, 40, 24, 56,
56 4, 36, 20, 52, 12, 44, 28, 60,
57 2, 34, 18, 50, 10, 42, 26, 58,
58 6, 38, 22, 54, 14, 46, 30, 62,
59 1, 33, 17, 49, 9, 41, 25, 57,
60 5, 37, 21, 53, 13, 45, 29, 61,
61 3, 35, 19, 51, 11, 43, 27, 59,
62 7, 39, 23, 55, 15, 47, 31, 63
63 };
64
65 // boradcast
66
67 vec256 tmp256[ GFBITS ];
68 vec256 x[ GFBITS ], y[ GFBITS ];
69
70 for (j = 0; j < 64; j += 8) {
71 for (i = 0; i < GFBITS; i++) {
72 t0 = (in[i] >> reversal[j + 0]) & 1;
73 t0 = -t0;
74 t1 = (in[i] >> reversal[j + 2]) & 1;
75 t1 = -t1;
76 t2 = (in[i] >> reversal[j + 4]) & 1;
77 t2 = -t2;
78 t3 = (in[i] >> reversal[j + 6]) & 1;
79 t3 = -t3;
80
81 out[j / 4 + 0][i] = PQCLEAN_MCELIECE348864F_AVX_vec256_set4x(t0, t1, t2, t3);
82
83 t0 = (in[i] >> reversal[j + 1]) & 1;
84 t0 = -t0;
85 t1 = (in[i] >> reversal[j + 3]) & 1;
86 t1 = -t1;
87 t2 = (in[i] >> reversal[j + 5]) & 1;
88 t2 = -t2;
89 t3 = (in[i] >> reversal[j + 7]) & 1;
90 t3 = -t3;
91
92 out[j / 4 + 1][i] = PQCLEAN_MCELIECE348864F_AVX_vec256_set4x(t0, t1, t2, t3);
93 }
94 }
95
96 //
97
98 for (i = 0; i < 16; i += 2) {
99 PQCLEAN_MCELIECE348864F_AVX_vec256_mul(tmp256, out[i + 1], consts[ 0 ]);
100
101 for (b = 0; b < GFBITS; b++) {
102 out[i + 0][b] ^= tmp256[b];
103 }
104 for (b = 0; b < GFBITS; b++) {
105 out[i + 1][b] ^= out[i + 0][b];
106 }
107 }
108
109 for (i = 0; i < 16; i += 2) {
110 for (b = 0; b < GFBITS; b++) {
111 x[b] = PQCLEAN_MCELIECE348864F_AVX_vec256_unpack_low_2x(out[i + 0][b], out[i + 1][b]);
112 }
113 for (b = 0; b < GFBITS; b++) {
114 y[b] = PQCLEAN_MCELIECE348864F_AVX_vec256_unpack_high_2x(out[i + 0][b], out[i + 1][b]);
115 }
116
117 PQCLEAN_MCELIECE348864F_AVX_vec256_mul(tmp256, y, consts[ 1 ]);
118
119 for (b = 0; b < GFBITS; b++) {
120 x[b] ^= tmp256[b];
121 }
122 for (b = 0; b < GFBITS; b++) {
123 y[b] ^= x[b];
124 }
125
126 for (b = 0; b < GFBITS; b++) {
127 out[i + 0][b] = PQCLEAN_MCELIECE348864F_AVX_vec256_unpack_low(x[b], y[b]);
128 }
129 for (b = 0; b < GFBITS; b++) {
130 out[i + 1][b] = PQCLEAN_MCELIECE348864F_AVX_vec256_unpack_high(x[b], y[b]);
131 }
132 }
133
134 consts_ptr = 2;
135
136 for (i = 0; i <= 3; i++) {
137 s = 1 << i;
138
139 for (j = 0; j < 16; j += 2 * s) {
140 for (k = j; k < j + s; k++) {
141 PQCLEAN_MCELIECE348864F_AVX_vec256_mul(tmp256, out[k + s], consts[ consts_ptr + (k - j) ]);
142
143 for (b = 0; b < GFBITS; b++) {
144 out[k][b] ^= tmp256[b];
145 }
146 for (b = 0; b < GFBITS; b++) {
147 out[k + s][b] ^= out[k][b];
148 }
149 }
150 }
151
152 consts_ptr += s;
153 }
154
155 // adding the part contributed by x^64
156
157 vec256 powers[16][GFBITS] = {
158 #include "powers.inc"
159 };
160
161 for (i = 0; i < 16; i++) {
162 for (b = 0; b < GFBITS; b++) {
163 out[i][b] = PQCLEAN_MCELIECE348864F_AVX_vec256_xor(out[i][b], powers[i][b]);
164 }
165 }
166 }
167
PQCLEAN_MCELIECE348864F_AVX_fft(vec256 out[][GFBITS],uint64_t * in)168 void PQCLEAN_MCELIECE348864F_AVX_fft(vec256 out[][ GFBITS ], uint64_t *in) {
169 radix_conversions(in);
170 butterflies(out, in);
171 }
172
173