-rw-r--r-- 1805 libmceliece-20240726/crypto_kem/348864/vec/vec.c raw
// 20221230 djb: add linker line
// linker define vec_mul vec_sq vec_inv
#include "vec.h"
#include "params.h"
void vec_mul(vec * h, const vec * f, const vec * g)
{
int i, j;
vec buf[ 2*GFBITS-1 ];
for (i = 0; i < 2*GFBITS-1; i++)
buf[i] = 0;
for (i = 0; i < GFBITS; i++)
for (j = 0; j < GFBITS; j++)
buf[i+j] ^= f[i] & g[j];
for (i = 2*GFBITS-2; i >= GFBITS; i--)
{
buf[i-GFBITS+3] ^= buf[i];
buf[i-GFBITS+0] ^= buf[i];
}
for (i = 0; i < GFBITS; i++)
h[i] = buf[i];
}
/* bitsliced field squarings */
void vec_sq(vec *out, vec *in)
{
int i;
uint64_t result[GFBITS];
//
result[0] = in[0]^in[6];
result[1] = in[11];
result[2] = in[1]^in[7];
result[3] = in[6];
result[4] = in[2] ^ in[11] ^ in[8];
result[5] = in[7];
result[6] = in[3]^in[9];
result[7] = in[8];
result[8] = in[4]^in[10];
result[9] = in[9];
result[10] = in[5] ^ in[11];
result[11] = in[10];
//
for (i = 0; i < GFBITS; i++)
out[i] = result[i];
}
/* bitsliced field inverses */
void vec_inv(vec *out, vec *in)
{
uint64_t tmp_11[GFBITS];
uint64_t tmp_1111[GFBITS];
vec_copy(out, in);
vec_sq(out, out);
vec_mul(tmp_11, out, in); // 11
vec_sq(out, tmp_11);
vec_sq(out, out);
vec_mul(tmp_1111, out, tmp_11); // 1111
vec_sq(out, tmp_1111);
vec_sq(out, out);
vec_sq(out, out);
vec_sq(out, out);
vec_mul(out, out, tmp_1111); // 11111111
vec_sq(out, out);
vec_sq(out, out);
vec_mul(out, out, tmp_11); // 1111111111
vec_sq(out, out);
vec_mul(out, out, in); // 11111111111
vec_sq(out, out); // 111111111110
}