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mirror of https://github.com/henrydcase/pqc.git synced 2024-11-26 17:31:38 +00:00
pqcrypto/crypto_kem/kyber512-90s/avx2/cbd.c
2019-09-24 08:01:54 +02:00

70 lines
2.6 KiB
C

#include "cbd.h"
#include "params.h"
#include <immintrin.h>
#include <stdint.h>
/*************************************************
* Name: cbd
*
* Description: Given an array of uniformly random bytes, compute
* polynomial with coefficients distributed according to
* a centered binomial distribution with parameter KYBER_ETA
*
* Arguments: - poly *r: pointer to output polynomial
* - const uint8_t *buf: pointer to input byte array
**************************************************/
void PQCLEAN_KYBER51290S_AVX2_cbd(poly *r, const uint8_t *buf) {
__m256i vec0, vec1, vec2, vec3, tmp;
const __m256i mask55 = _mm256_set1_epi32(0x55555555);
const __m256i mask33 = _mm256_set1_epi32(0x33333333);
const __m256i mask03 = _mm256_set1_epi32(0x03030303);
for (size_t i = 0; i < KYBER_N / 64; i++) {
vec0 = _mm256_loadu_si256((__m256i *)&buf[32 * i]);
vec1 = _mm256_srli_epi32(vec0, 1);
vec0 = _mm256_and_si256(mask55, vec0);
vec1 = _mm256_and_si256(mask55, vec1);
vec0 = _mm256_add_epi32(vec0, vec1);
vec1 = _mm256_srli_epi32(vec0, 2);
vec0 = _mm256_and_si256(mask33, vec0);
vec1 = _mm256_and_si256(mask33, vec1);
vec2 = _mm256_srli_epi32(vec0, 4);
vec3 = _mm256_srli_epi32(vec1, 4);
vec0 = _mm256_and_si256(mask03, vec0);
vec1 = _mm256_and_si256(mask03, vec1);
vec2 = _mm256_and_si256(mask03, vec2);
vec3 = _mm256_and_si256(mask03, vec3);
vec1 = _mm256_sub_epi8(vec0, vec1);
vec3 = _mm256_sub_epi8(vec2, vec3);
vec0 = _mm256_cvtepi8_epi16(_mm256_castsi256_si128(vec1));
vec1 = _mm256_cvtepi8_epi16(_mm256_extracti128_si256(vec1, 1));
vec2 = _mm256_cvtepi8_epi16(_mm256_castsi256_si128(vec3));
vec3 = _mm256_cvtepi8_epi16(_mm256_extracti128_si256(vec3, 1));
tmp = _mm256_unpacklo_epi16(vec0, vec2);
vec2 = _mm256_unpackhi_epi16(vec0, vec2);
vec0 = tmp;
tmp = _mm256_unpacklo_epi16(vec1, vec3);
vec3 = _mm256_unpackhi_epi16(vec1, vec3);
vec1 = tmp;
tmp = _mm256_permute2x128_si256(vec0, vec2, 0x20);
vec2 = _mm256_permute2x128_si256(vec0, vec2, 0x31);
vec0 = tmp;
tmp = _mm256_permute2x128_si256(vec1, vec3, 0x20);
vec3 = _mm256_permute2x128_si256(vec1, vec3, 0x31);
vec1 = tmp;
_mm256_store_si256((__m256i *)&r->coeffs[64 * i + 0], vec0);
_mm256_store_si256((__m256i *)&r->coeffs[64 * i + 16], vec2);
_mm256_store_si256((__m256i *)&r->coeffs[64 * i + 32], vec1);
_mm256_store_si256((__m256i *)&r->coeffs[64 * i + 48], vec3);
}
}