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pqcrypto/crypto_kem/ntrulpr761/avx2/crypto_decode_761x3.c

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#include "crypto_decode_761x3.h"
#include <immintrin.h>
#define uint8 uint8_t
#define p 761
#define loops 6
#define overshoot 2
void PQCLEAN_NTRULPR761_AVX2_crypto_decode_761x3(void *v, const unsigned char *s) {
uint8 *f = v;
int loop;
uint8 *nextf = f + 128 - 4 * overshoot;
const unsigned char *nexts = s + 32 - overshoot;
for (loop = loops; loop > 0; --loop) {
__m256i s0 = _mm256_loadu_si256((const __m256i *) s);
s = nexts;
nexts += 32;
__m256i s1 = _mm256_srli_epi16(s0 & _mm256_set1_epi8(-16), 4);
s0 &= _mm256_set1_epi8(15);
__m256i a0 = _mm256_unpacklo_epi8(s0, s1);
/* 0 0>>4 1 1>>4 2 2>>4 3 3>>4 4 4>>4 5 5>>4 6 6>>4 7 7>>4 */
/* 16 16>>4 ... */
__m256i a1 = _mm256_unpackhi_epi8(s0, s1);
/* 8 8>>4 9 9>>4 10 10>>4 ... */
/* 24 24>>4 ... */
__m256i a2 = _mm256_srli_epi16(a0 & _mm256_set1_epi8(12), 2);
__m256i a3 = _mm256_srli_epi16(a1 & _mm256_set1_epi8(12), 2);
a0 &= _mm256_set1_epi8(3);
a1 &= _mm256_set1_epi8(3);
__m256i b0 = _mm256_unpacklo_epi8(a0, a2);
/* 0 0>>2 0>>4 0>>6 1 1>>2 1>>4 1>>6 */
/* 2 2>>2 2>>4 2>>6 3 3>>2 3>>4 3>.6 */
/* 16 16>>2 16>>4 16>>6 ... */
__m256i b2 = _mm256_unpackhi_epi8(a0, a2);
/* 4 4>>2 ... */
__m256i b1 = _mm256_unpacklo_epi8(a1, a3);
/* 8 8>>2 ... */
__m256i b3 = _mm256_unpackhi_epi8(a1, a3);
/* 12 12>>2 ... */
__m256i f0 = _mm256_permute2x128_si256(b0, b2, 0x20);
__m256i f2 = _mm256_permute2x128_si256(b0, b2, 0x31);
__m256i f1 = _mm256_permute2x128_si256(b1, b3, 0x20);
__m256i f3 = _mm256_permute2x128_si256(b1, b3, 0x31);
f0 = _mm256_add_epi8(f0, _mm256_set1_epi8(-1));
f1 = _mm256_add_epi8(f1, _mm256_set1_epi8(-1));
f2 = _mm256_add_epi8(f2, _mm256_set1_epi8(-1));
f3 = _mm256_add_epi8(f3, _mm256_set1_epi8(-1));
_mm256_storeu_si256((__m256i *) (f + 0), f0);
_mm256_storeu_si256((__m256i *) (f + 32), f1);
_mm256_storeu_si256((__m256i *) (f + 64), f2);
_mm256_storeu_si256((__m256i *) (f + 96), f3);
f = nextf;
nextf += 128;
}
*f = ((uint8)(*s & 3)) - 1;
}