-rw-r--r-- 1857 libmceliece-20240726/crypto_kem/460896/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+4] ^= buf[i];
buf[i-GFBITS+3] ^= buf[i];
buf[i-GFBITS+1] ^= 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;
vec result[GFBITS], t;
t = in[11] ^ in[12];
result[0] = in[0] ^ in[11];
result[1] = in[7] ^ t;
result[2] = in[1] ^ in[7];
result[3] = in[8] ^ t;
result[4] = in[2] ^ in[7];
result[4] = result[4] ^ in[8];
result[4] = result[4] ^ t;
result[5] = in[7] ^ in[9];
result[6] = in[3] ^ in[8];
result[6] = result[6] ^ in[9];
result[6] = result[6] ^ in[12];
result[7] = in[8] ^ in[10];
result[8] = in[4] ^ in[9];
result[8] = result[8] ^ in[10];
result[9] = in[9] ^ in[11];
result[10] = in[5] ^ in[10];
result[10] = result[10] ^ in[11];
result[11] = in[10] ^ in[12];
result[12] = in[6] ^ t;
for (i = 0; i < GFBITS; i++)
out[i] = result[i];
}
/* bitsliced field inverses */
void vec_inv(vec * out, vec * in)
{
vec tmp_11[ GFBITS ];
vec 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_sq(out, out);
vec_sq(out, out);
vec_mul(out, out, tmp_1111); // ^111111111111
vec_sq(out, out); // ^1111111111110
}