-rw-r--r-- 1873 libmceliece-20240726/crypto_kem/460896/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], t;

	t = vec256_xor(in[11], in[12]);

	result[0] = vec256_xor(in[0], in[11]);
	result[1] = vec256_xor(in[7], t);
	result[2] = vec256_xor(in[1], in[7]);
	result[3] = vec256_xor(in[8], t);
	result[4] = vec256_xor(in[2], in[7]);
	result[4] = vec256_xor(result[4], in[8]);
	result[4] = vec256_xor(result[4], t);
	result[5] = vec256_xor(in[7], in[9]);
	result[6] = vec256_xor(in[3], in[8]);
	result[6] = vec256_xor(result[6], in[9]);
	result[6] = vec256_xor(result[6], in[12]);
	result[7] = vec256_xor(in[8], in[10]);
	result[8] = vec256_xor(in[4], in[9]);
	result[8] = vec256_xor(result[8], in[10]);
	result[9] = vec256_xor(in[9], in[11]);
	result[10] = vec256_xor(in[5], in[10]);
	result[10] = vec256_xor(result[10], in[11]);
	result[11] = vec256_xor(in[10], in[12]);
	result[12] = vec256_xor(in[6], t);

	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_sq(out, out);
	vec256_sq(out, out);
	vec256_mul(out, out, tmp_1111); // ^111111111111

	vec256_sq(out, out); // ^1111111111110
}