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Final version of kernal function, now we save 320 us with the intrinsics

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Martino
2018-06-18 09:40:29 +02:00
parent 4626a85dbf
commit d4fbc3a14d
1 changed files with 34 additions and 38 deletions
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openair1/PHY/CODING/nrPolar_tools/nr_polar_kernal_operation.c
+34 -38
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@@ -10,70 +10,66 @@ void nr_polar_kernal_operation(uint8_t *u, uint8_t *d, uint16_t N)
// Martino's algorithm to avoid multiplication for the generating matrix of polar codes
uint32_t i,j;
for(i=0; i<N; i++) // Create the elements of d=u*G_N ...
{
d[i]=0;
for(j=0; j<N; j++) // ... looking at all the elements of u
{
d[i]=d[i] ^ (!( (j-i)& i ))*u[j];
}
}
#ifdef __AVX2__
/*
* It works, but there are too many moves from memory and it's slow. With AVX-512 it could be done faster
*
__m256i A,B,C,E,U, OUT;
__m256i A,B,C,D,E,U,zerosOnly, OUT;
__m256i inc;
uint32_t dTest[8];
uint32_t uArray[8];
uint32_t k;
uint32_t toCheck[8];
uint32_t incArray[8];
for(k=0; k<8; k++)
incArray[k]=k; //0,1, ... 7
inc=_mm256_loadu_si256((__m256i const*)incArray);
//initialisation
for(k=0; k<8; k++)
incArray[k]=k;
inc=_mm256_loadu_si256((__m256i const*)incArray); // 0, 1, ..., 7 to increase
zerosOnly=_mm256_setzero_si256(); // for comparison
for(i=0; i<N; i+=8)
{
B=_mm256_set1_epi32((int)i); // i, ... i
B=_mm256_add_epi32(B, inc); //i, i+1, ... i+7
B=_mm256_set1_epi32((int)i); // i, ..., i
B=_mm256_add_epi32(B, inc); // i, i+1, ..., i+7
OUT=_mm256_setzero_si256();
OUT=_mm256_setzero_si256(); // it will contain the result of all the XORs for the d(i)s
for(j=0; j<N; j++)
{
//initialisation
A=_mm256_set1_epi32((int)(j)); //j ...
A=_mm256_set1_epi32((int)(j)); //j, j, ..., j
A=_mm256_sub_epi32(A, B); //(j-i), (j-(i+1)), ... (j-(i+7))
U=_mm256_set1_epi32((int)u[j]);
_mm256_storeu_si256((__m256i*)uArray, U); //u(j) ... u(j) for the maskload
C=_mm256_and_si256(A, B); //mask: if zero, then add
_mm256_storeu_si256((__m256i*)toCheck, C);
for(k=0; k<8; k++)
{
toCheck[k]=!toCheck[k] << 31;
}
C=_mm256_loadu_si256((__m256i const*)toCheck); //mask: if 1, add
E=_mm256_maskload_epi32((int const*)uArray, C);
C=_mm256_and_si256(A, B); //(j-i)&i -> If zero, then XOR with the u(j)
D=_mm256_cmpeq_epi32(C, zerosOnly); // compare with zero and use the result as mask
E=_mm256_maskload_epi32((int const*)uArray, D); // load only some u(j)s for the XOR
OUT=_mm256_xor_si256(OUT, E); //32 bit x 8
}
_mm256_storeu_si256((__m256i*)dTest, OUT);
for(k=0; k<8; k++)
for(k=0; k<8; k++) // Conversion from 32 bits to 8 bits
{
d[i+k]=(uint8_t)dTest[k]; //Conv from 32 to 8
d[i+k]=(uint8_t)dTest[k]; // With AVX512 there is an intrinsic to do it
}
}
*/
#else
for(i=0; i<N; i++) // Create the elements of d=u*G_N ...
{
d[i]=0;
for(j=0; j<N; j++) // ... looking at all the elements of u
{
d[i]=d[i] ^ (!( (j-i)& i ))*u[j];
// it's like ((j-i)&i)==0
}
}
#endif
}