-rw-r--r-- 1384 libmceliece-20241009/crypto_kem/348864/avx/vec256.c raw
// 20240508 djb: include vec256_gf.h
// 20221230 djb: add linker line

// linker define vec256_sq vec256_inv
// linker use vec256_mul_asm

/*
  This file is for functions related to 256-bit vectors
  including functions for bitsliced field operations
*/

#include "vec256_gf.h"

/* bitsliced field squarings */
void vec256_sq(vec256 * out, vec256 * in)
{
	int i;
	vec256 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 vec256_inv(vec256 * out, vec256 * in)
{
	vec256 tmp_11[ GFBITS ];
	vec256 tmp_1111[ GFBITS ];

	vec256_copy(out, in);

	vec256_sq(out, out);
	vec256_mul(tmp_11, out, in); // ^11

	vec256_sq(out, tmp_11);
	vec256_sq(out, out);
	vec256_mul(tmp_1111, out, tmp_11); // ^1111

	vec256_sq(out, tmp_1111);
	vec256_sq(out, out);
	vec256_sq(out, out);
	vec256_sq(out, out);
	vec256_mul(out, out, tmp_1111); // ^11111111

	vec256_sq(out, out);
	vec256_sq(out, out);
	vec256_mul(out, out, tmp_11); // ^1111111111
	vec256_sq(out, out);
	vec256_mul(out, out, in); // ^11111111111

	vec256_sq(out, out); // ^111111111110
}