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openairinterface5g/openair1/PHY/CODING/nrPolar_tools/nr_polar_decoder.c
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/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance
* contact@openairinterface.org
*/
/*!\file PHY/CODING/nrPolar_tools/nr_polar_decoder.c
* \brief
* \author Raymond Knopp, Turker Yilmaz
* \date 2018
* \version 0.1
* \company EURECOM
* \email raymond.knopp@eurecom.fr, turker.yilmaz@eurecom.fr
* \note
* \warning
*/
/*
* Return values:
* 0 --> Success
* -1 --> All list entries have failed the CRC checks
*/
#include "PHY/CODING/nrPolar_tools/nr_polar_defs.h"
#include "assertions.h"
static inline void updateCrcChecksum2(int xlen,
int ylen,
uint8_t crcChecksum[xlen][ylen],
int gxlen,
int gylen,
uint8_t crcGen[gxlen][gylen],
uint8_t listSize,
uint32_t i2,
uint8_t len)
{
for (uint8_t i = 0; i < listSize; i++) {
for (uint8_t j = 0; j < len; j++) {
crcChecksum[j][i+listSize] = ( (crcChecksum[j][i] + crcGen[i2][j]) % 2 );
}
}
}
int8_t polar_decoder(double *input,
uint32_t *out,
uint8_t listSize,
int8_t messageType,
uint16_t messageLength,
uint8_t aggregation_level
)
{
t_nrPolar_params *polarParams=nr_polar_params(messageType, messageLength, aggregation_level, true);
//Assumes no a priori knowledge.
uint8_t bit[polarParams->N][polarParams->n+1][2*listSize];
memset(bit,0,sizeof bit);
uint8_t bitUpdated[polarParams->N][polarParams->n+1]; //0=False, 1=True
memset(bitUpdated,0,sizeof bitUpdated);
uint8_t llrUpdated[polarParams->N][polarParams->n+1]; //0=False, 1=True
memset(llrUpdated,0,sizeof llrUpdated);
double llr[polarParams->N][polarParams->n+1][2*listSize];
uint8_t crcChecksum[polarParams->crcParityBits][2*listSize];
memset(crcChecksum,0,sizeof crcChecksum);
double pathMetric[2*listSize];
uint8_t crcState[2*listSize]; //0=False, 1=True
for (int i=0; i<(2*listSize); i++) {
pathMetric[i] = 0;
crcState[i]=1;
}
for (int i=0; i<polarParams->N; i++) {
llrUpdated[i][polarParams->n]=1;
bitUpdated[i][0]=((polarParams->information_bit_pattern[i]+1) % 2);
}
uint8_t extended_crc_generator_matrix[polarParams->K][polarParams->crcParityBits]; //G_P3
uint8_t tempECGM[polarParams->K][polarParams->crcParityBits]; //G_P2
for (int i=0; i<polarParams->payloadBits; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
tempECGM[i][j]=polarParams->crc_generator_matrix[i][j];
}
}
for (int i=polarParams->payloadBits; i<polarParams->K; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
if( (i-polarParams->payloadBits) == j ) {
tempECGM[i][j]=1;
} else {
tempECGM[i][j]=0;
}
}
}
for (int i=0; i<polarParams->K; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
extended_crc_generator_matrix[i][j]=tempECGM[polarParams->interleaving_pattern[i]][j];
}
}
//The index of the last 1-valued bit that appears in each column.
uint16_t last1ind[polarParams->crcParityBits];
for (int j=0; j<polarParams->crcParityBits; j++) {
for (int i=0; i<polarParams->K; i++) {
if (extended_crc_generator_matrix[i][j]==1) last1ind[j]=i;
}
}
double d_tilde[polarParams->N];
nr_polar_rate_matching(input, d_tilde, polarParams->rate_matching_pattern, polarParams->K, polarParams->N, polarParams->encoderLength);
for (int j = 0; j < polarParams->N; j++) llr[j][polarParams->n][0]=d_tilde[j];
/*
* SCL polar decoder.
*/
uint32_t nonFrozenBit=0;
uint8_t currentListSize=1;
uint8_t decoderIterationCheck=0;
int16_t checkCrcBits=-1;
uint8_t listIndex[2*listSize], copyIndex;
for (uint16_t currentBit=0; currentBit<polarParams->N; currentBit++) {
updateLLR(currentListSize, currentBit, 0, polarParams->N, polarParams->n+1, 2*listSize, llr, llrUpdated, bit, bitUpdated);
if (polarParams->information_bit_pattern[currentBit]==0) { //Frozen bit.
updatePathMetric(pathMetric, currentListSize, 0, currentBit, polarParams->N, polarParams->n+1, 2*listSize, llr);
} else { //Information or CRC bit.
updatePathMetric2(pathMetric, currentListSize, currentBit, polarParams->N, polarParams->n+1, 2*listSize, llr);
for (int i = 0; i < currentListSize; i++) {
for (int j = 0; j < polarParams->N; j++) {
for (int k = 0; k < (polarParams->n+1); k++) {
bit[j][k][i+currentListSize]=bit[j][k][i];
llr[j][k][i+currentListSize]=llr[j][k][i];
}
}
}
for (int i = 0; i < currentListSize; i++) {
bit[currentBit][0][i]=0;
crcState[i+currentListSize]=crcState[i];
}
for (int i = currentListSize; i < 2*currentListSize; i++) bit[currentBit][0][i]=1;
bitUpdated[currentBit][0]=1;
updateCrcChecksum2(polarParams->crcParityBits, 2*listSize, crcChecksum,
polarParams->K, polarParams->crcParityBits, extended_crc_generator_matrix,
currentListSize, nonFrozenBit, polarParams->crcParityBits);
currentListSize*=2;
//Keep only the best "listSize" number of entries.
if (currentListSize > listSize) {
for (uint8_t i = 0; i < 2*listSize; i++) listIndex[i]=i;
nr_sort_asc_double_1D_array_ind(pathMetric, listIndex, currentListSize);
//sort listIndex[listSize, ..., 2*listSize-1] in descending order.
uint8_t swaps, tempInd;
for (uint8_t i = 0; i < listSize; i++) {
swaps = 0;
for (uint8_t j = listSize; j < (2*listSize - i) - 1; j++) {
if (listIndex[j+1] > listIndex[j]) {
tempInd = listIndex[j];
listIndex[j] = listIndex[j + 1];
listIndex[j + 1] = tempInd;
swaps++;
}
}
if (swaps == 0)
break;
}
//First, backup the best "listSize" number of entries.
for (int k=(listSize-1); k>0; k--) {
for (int i=0; i<polarParams->N; i++) {
for (int j=0; j<(polarParams->n+1); j++) {
bit[i][j][listIndex[(2*listSize-1)-k]]=bit[i][j][listIndex[k]];
llr[i][j][listIndex[(2*listSize-1)-k]]=llr[i][j][listIndex[k]];
}
}
}
for (int k=(listSize-1); k>0; k--) {
for (int i = 0; i < polarParams->crcParityBits; i++) {
crcChecksum[i][listIndex[(2*listSize-1)-k]] = crcChecksum[i][listIndex[k]];
}
}
for (int k=(listSize-1); k>0; k--) crcState[listIndex[(2*listSize-1)-k]]=crcState[listIndex[k]];
//Copy the best "listSize" number of entries to the first indices.
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
for (int i = 0; i < polarParams->N; i++) {
for (int j = 0; j < (polarParams->n + 1); j++) {
bit[i][j][k] = bit[i][j][copyIndex];
llr[i][j][k] = llr[i][j][copyIndex];
}
}
}
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
for (int i = 0; i < polarParams->crcParityBits; i++) {
crcChecksum[i][k]=crcChecksum[i][copyIndex];
}
}
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
crcState[k]=crcState[copyIndex];
}
currentListSize = listSize;
}
for (int i=0; i<polarParams->crcParityBits; i++) {
if (last1ind[i]==nonFrozenBit) {
checkCrcBits=i;
break;
}
}
if ( checkCrcBits > (-1) ) {
for (uint8_t i = 0; i < currentListSize; i++) {
if (crcChecksum[checkCrcBits][i]==1) {
crcState[i]=0; //0=False, 1=True
}
}
}
for (uint8_t i = 0; i < currentListSize; i++) decoderIterationCheck+=crcState[i];
if (decoderIterationCheck==0) {
//perror("[SCL polar decoder] All list entries have failed the CRC checks.");
polarReturn(-1);
}
nonFrozenBit++;
decoderIterationCheck=0;
checkCrcBits=-1;
}
}
for (uint8_t i = 0; i < 2*listSize; i++) listIndex[i]=i;
nr_sort_asc_double_1D_array_ind(pathMetric, listIndex, currentListSize);
for (uint8_t i = 0; i < fmin(listSize, (pow(2,polarParams->crcCorrectionBits)) ); i++) {
if ( crcState[listIndex[i]] == 1 ) {
for (int j = 0; j < polarParams->N; j++) polarParams->nr_polar_U[j]=bit[j][0][listIndex[i]];
//Extract the information bits (û to ĉ)
nr_polar_info_bit_extraction(polarParams->nr_polar_U, polarParams->nr_polar_CPrime, polarParams->information_bit_pattern, polarParams->N);
//Deinterleaving (ĉ to b)
nr_polar_deinterleaver(polarParams->nr_polar_CPrime, polarParams->nr_polar_B, polarParams->interleaving_pattern, polarParams->K);
//Remove the CRC (â)
for (int j = 0; j < polarParams->payloadBits; j++) polarParams->nr_polar_A[j]=polarParams->nr_polar_B[j];
break;
}
}
/*
* Return bits.
*/
nr_byte2bit_uint8_32(polarParams->nr_polar_A, polarParams->payloadBits, out);
polarReturn 0;
}
int8_t polar_decoder_dci(double *input,
uint32_t *out,
uint8_t listSize,
uint16_t n_RNTI,
int8_t messageType,
uint16_t messageLength,
uint8_t aggregation_level ) {
t_nrPolar_params *polarParams=nr_polar_params(messageType, messageLength, aggregation_level, true);
uint8_t bit[polarParams->N][polarParams->n+1][2*listSize];
memset(bit,0,sizeof bit);
uint8_t bitUpdated[polarParams->N][polarParams->n+1]; //0=False, 1=True
memset(bitUpdated,0,sizeof bitUpdated);
uint8_t llrUpdated[polarParams->N][polarParams->n+1]; //0=False, 1=True
memset(llrUpdated,0,sizeof llrUpdated);
double llr[polarParams->N][polarParams->n+1][2*listSize];
uint8_t crcChecksum[polarParams->crcParityBits][2*listSize];
memset(crcChecksum,0,sizeof crcChecksum);
double pathMetric[2*listSize];
uint8_t crcState[2*listSize]; //0=False, 1=True
uint8_t extended_crc_scrambling_pattern[polarParams->crcParityBits];
for (int i=0; i<(2*listSize); i++) {
pathMetric[i] = 0;
crcState[i]=1;
}
for (int i=0; i<polarParams->N; i++) {
llrUpdated[i][polarParams->n]=1;
bitUpdated[i][0]=((polarParams->information_bit_pattern[i]+1) % 2);
}
uint8_t extended_crc_generator_matrix[polarParams->K][polarParams->crcParityBits]; //G_P3: K-by-P
uint8_t tempECGM[polarParams->K][polarParams->crcParityBits]; //G_P2: K-by-P
for (int i=0; i<polarParams->payloadBits; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
tempECGM[i][j]=polarParams->crc_generator_matrix[i+polarParams->crcParityBits][j];
}
}
for (int i=polarParams->payloadBits; i<polarParams->K; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
if( (i-polarParams->payloadBits) == j ) {
tempECGM[i][j]=1;
} else {
tempECGM[i][j]=0;
}
}
}
for (int i=0; i<polarParams->K; i++) {
for (int j=0; j<polarParams->crcParityBits; j++) {
extended_crc_generator_matrix[i][j]=tempECGM[polarParams->interleaving_pattern[i]][j];
}
}
//The index of the last 1-valued bit that appears in each column.
uint16_t last1ind[polarParams->crcParityBits];
for (int j=0; j<polarParams->crcParityBits; j++) {
for (int i=0; i<polarParams->K; i++) {
if (extended_crc_generator_matrix[i][j]==1) last1ind[j]=i;
}
}
for (int i=0; i<8; i++) extended_crc_scrambling_pattern[i]=0;
for (int i=8; i<polarParams->crcParityBits; i++) {
extended_crc_scrambling_pattern[i]=(n_RNTI>>(23-i))&1;
}
double d_tilde[polarParams->N];
nr_polar_rate_matching(input, d_tilde, polarParams->rate_matching_pattern, polarParams->K, polarParams->N, polarParams->encoderLength);
for (int j = 0; j < polarParams->N; j++)
llr[j][polarParams->n][0]=d_tilde[j];
/*
* SCL polar decoder.
*/
for (int i=0; i<polarParams->crcParityBits; i++) {
for (int j=0; j<polarParams->crcParityBits; j++)
crcChecksum[i][0]=crcChecksum[i][0]+polarParams->crc_generator_matrix[j][i];
crcChecksum[i][0]=(crcChecksum[i][0]%2);
}
uint32_t nonFrozenBit=0;
uint8_t currentListSize=1;
uint8_t decoderIterationCheck=0;
int16_t checkCrcBits=-1;
uint8_t listIndex[2*listSize], copyIndex;
for (uint16_t currentBit=0; currentBit<polarParams->N; currentBit++) {
updateLLR(currentListSize, currentBit, 0, polarParams->N, polarParams->n+1, 2*listSize, llr, llrUpdated, bit, bitUpdated);
if (polarParams->information_bit_pattern[currentBit]==0) { //Frozen bit.
updatePathMetric(pathMetric, currentListSize, 0, currentBit,polarParams->N, polarParams->n+1, 2*listSize, llr);
} else { //Information or CRC bit.
updatePathMetric2(pathMetric, currentListSize, currentBit, polarParams->N, polarParams->n+1, 2*listSize, llr);
for (int i = 0; i < currentListSize; i++) {
for (int j = 0; j < polarParams->N; j++) {
for (int k = 0; k < (polarParams->n+1); k++) {
bit[j][k][i+currentListSize]=bit[j][k][i];
llr[j][k][i+currentListSize]=llr[j][k][i];
}
}
}
for (int i = 0; i < currentListSize; i++) {
bit[currentBit][0][i]=0;
crcState[i+currentListSize]=crcState[i];
}
for (int i = currentListSize; i < 2*currentListSize; i++) bit[currentBit][0][i]=1;
bitUpdated[currentBit][0]=1;
updateCrcChecksum2(polarParams->crcParityBits, 2*listSize, crcChecksum,
polarParams->K, polarParams->crcParityBits, extended_crc_generator_matrix,
currentListSize, nonFrozenBit, polarParams->crcParityBits);
currentListSize*=2;
//Keep only the best "listSize" number of entries.
if (currentListSize > listSize) {
for (uint8_t i = 0; i < 2*listSize; i++) listIndex[i]=i;
nr_sort_asc_double_1D_array_ind(pathMetric, listIndex, currentListSize);
//sort listIndex[listSize, ..., 2*listSize-1] in descending order.
uint8_t swaps, tempInd;
for (uint8_t i = 0; i < listSize; i++) {
swaps = 0;
for (uint8_t j = listSize; j < (2*listSize - i) - 1; j++) {
if (listIndex[j+1] > listIndex[j]) {
tempInd = listIndex[j];
listIndex[j] = listIndex[j + 1];
listIndex[j + 1] = tempInd;
swaps++;
}
}
if (swaps == 0)
break;
}
//First, backup the best "listSize" number of entries.
for (int k=(listSize-1); k>0; k--) {
for (int i=0; i<polarParams->N; i++) {
for (int j=0; j<(polarParams->n+1); j++) {
bit[i][j][listIndex[(2*listSize-1)-k]]=bit[i][j][listIndex[k]];
llr[i][j][listIndex[(2*listSize-1)-k]]=llr[i][j][listIndex[k]];
}
}
}
for (int k=(listSize-1); k>0; k--) {
for (int i = 0; i < polarParams->crcParityBits; i++) {
crcChecksum[i][listIndex[(2*listSize-1)-k]] = crcChecksum[i][listIndex[k]];
}
}
for (int k=(listSize-1); k>0; k--) crcState[listIndex[(2*listSize-1)-k]]=crcState[listIndex[k]];
//Copy the best "listSize" number of entries to the first indices.
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
for (int i = 0; i < polarParams->N; i++) {
for (int j = 0; j < (polarParams->n + 1); j++) {
bit[i][j][k] = bit[i][j][copyIndex];
llr[i][j][k] = llr[i][j][copyIndex];
}
}
}
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
for (int i = 0; i < polarParams->crcParityBits; i++) {
crcChecksum[i][k]=crcChecksum[i][copyIndex];
}
}
for (int k = 0; k < listSize; k++) {
if (k > listIndex[k]) {
copyIndex = listIndex[(2*listSize-1)-k];
} else { //Use the backup.
copyIndex = listIndex[k];
}
crcState[k]=crcState[copyIndex];
}
currentListSize = listSize;
}
for (int i=0; i<polarParams->crcParityBits; i++) {
if (last1ind[i]==nonFrozenBit) {
checkCrcBits=i;
break;
}
}
if ( checkCrcBits > (-1) ) {
for (uint8_t i = 0; i < currentListSize; i++) {
if (crcChecksum[checkCrcBits][i]!=extended_crc_scrambling_pattern[checkCrcBits]) {
crcState[i]=0; //0=False, 1=True
}
}
}
for (uint8_t i = 0; i < currentListSize; i++)
decoderIterationCheck+=crcState[i];
if (decoderIterationCheck==0) {
//perror("[SCL polar decoder] All list entries have failed the CRC checks.");
polarReturn -1;
}
nonFrozenBit++;
decoderIterationCheck=0;
checkCrcBits=-1;
}
}
for (uint8_t i = 0; i < 2*listSize; i++) listIndex[i]=i;
nr_sort_asc_double_1D_array_ind(pathMetric, listIndex, currentListSize);
for (uint8_t i = 0; i < fmin(listSize, (pow(2,polarParams->crcCorrectionBits)) ); i++) {
if ( crcState[listIndex[i]] == 1 ) {
for (int j = 0; j < polarParams->N; j++) polarParams->nr_polar_U[j]=bit[j][0][listIndex[i]];
//Extract the information bits (û to ĉ)
nr_polar_info_bit_extraction(polarParams->nr_polar_U, polarParams->nr_polar_CPrime, polarParams->information_bit_pattern, polarParams->N);
//Deinterleaving (ĉ to b)
nr_polar_deinterleaver(polarParams->nr_polar_CPrime, polarParams->nr_polar_B, polarParams->interleaving_pattern, polarParams->K);
//Remove the CRC (â)
for (int j = 0; j < polarParams->payloadBits; j++) polarParams->nr_polar_A[j]=polarParams->nr_polar_B[j];
break;
}
}
/*
* Return bits.
*/
nr_byte2bit_uint8_32(polarParams->nr_polar_A, polarParams->payloadBits, out);
polarReturn 0;
}
void init_polar_deinterleaver_table(t_nrPolar_params *polarParams) {
AssertFatal(polarParams->K > 17, "K = %d < 18, is not allowed\n",polarParams->K);
AssertFatal(polarParams->K < 129, "K = %d > 128, is not supported yet\n",polarParams->K);
int bit_i,ip,ipmod64;
int numbytes = polarParams->K>>3;
int residue = polarParams->K&7;
int numbits;
if (residue>0) numbytes++;
for (int byte=0; byte<numbytes; byte++) {
if (byte<(polarParams->K>>3)) numbits=8;
else numbits=residue;
for (int i=0; i<numbits; i++) {
// flip bit endian for B
ip=polarParams->K - 1 - polarParams->interleaving_pattern[(8*byte)+i];
#if 0
printf("byte %d, i %d => ip %d\n",byte,i,ip);
#endif
ipmod64 = ip&63;
AssertFatal(ip<128,"ip = %d\n",ip);
for (int val=0; val<256; val++) {
bit_i=(val>>i)&1;
if (ip<64) polarParams->B_tab0[byte][val] |= (((uint64_t)bit_i)<<ipmod64);
else polarParams->B_tab1[byte][val] |= (((uint64_t)bit_i)<<ipmod64);
}
}
}
}
uint32_t polar_decoder_int16(int16_t *input,
uint64_t *out,
uint8_t ones_flag,
int8_t messageType,
uint16_t messageLength,
uint8_t aggregation_level )
{
t_nrPolar_params *polarParams=nr_polar_params(messageType, messageLength, aggregation_level, true);
int16_t d_tilde[polarParams->N];// = malloc(sizeof(double) * polarParams->N);
nr_polar_rate_matching_int16(input, d_tilde, polarParams->rate_matching_pattern, polarParams->K, polarParams->N, polarParams->encoderLength);
for (int i=0; i<polarParams->N; i++) {
if (d_tilde[i]<-128) d_tilde[i]=-128;
else if (d_tilde[i]>127) d_tilde[i]=128;
}
memcpy((void *)&polarParams->tree.root->alpha[0],(void *)&d_tilde[0],sizeof(int16_t)*polarParams->N);
generic_polar_decoder(polarParams,polarParams->tree.root);
//Extract the information bits (û to ĉ)
uint64_t Cprime[4]= {0,0,0,0};
uint64_t B[4]= {0,0,0,0};
for (int i=0; i<polarParams->K; i++) Cprime[i>>6] = Cprime[i>>6] | ((uint64_t)polarParams->nr_polar_U[polarParams->Q_I_N[i]])<<(i&63);
//Deinterleaving (ĉ to b)
uint8_t *Cprimebyte = (uint8_t *)Cprime;
if (polarParams->K<65) {
B[0] = polarParams->B_tab0[0][Cprimebyte[0]] |
polarParams->B_tab0[1][Cprimebyte[1]] |
polarParams->B_tab0[2][Cprimebyte[2]] |
polarParams->B_tab0[3][Cprimebyte[3]] |
polarParams->B_tab0[4][Cprimebyte[4]] |
polarParams->B_tab0[5][Cprimebyte[5]] |
polarParams->B_tab0[6][Cprimebyte[6]] |
polarParams->B_tab0[7][Cprimebyte[7]];
} else if (polarParams->K<129) {
int len = polarParams->K/8;
if ((polarParams->K&7) > 0) len++;
for (int k=0; k<len; k++) {
B[0] |= polarParams->B_tab0[k][Cprimebyte[k]];
B[1] |= polarParams->B_tab1[k][Cprimebyte[k]];
}
}
int len=polarParams->payloadBits;
//int len_mod64=len&63;
int crclen = polarParams->crcParityBits;
uint64_t rxcrc=B[0]&((1<<crclen)-1);
uint32_t crc = 0;
uint64_t Ar = 0;
AssertFatal(len<65,"A must be less than 65 bits\n");
// appending 24 ones before a0 for DCI as stated in 38.212 7.3.2
uint8_t offset = 0;
if (ones_flag) offset = 3;
if (len<=32) {
Ar = (uint32_t)(B[0]>>crclen);
uint8_t A32_flip[4+offset];
if (ones_flag) {
A32_flip[0] = 0xff;
A32_flip[1] = 0xff;
A32_flip[2] = 0xff;
}
uint32_t Aprime= (uint32_t)(Ar<<(32-len));
A32_flip[0+offset]=((uint8_t *)&Aprime)[3];
A32_flip[1+offset]=((uint8_t *)&Aprime)[2];
A32_flip[2+offset]=((uint8_t *)&Aprime)[1];
A32_flip[3+offset]=((uint8_t *)&Aprime)[0];
if (crclen == 24) crc = (uint64_t)((crc24c(A32_flip,8*offset+len)>>8)&0xffffff);
else if (crclen == 11) crc = (uint64_t)((crc11(A32_flip,8*offset+len)>>21)&0x7ff);
else if (crclen == 6) crc = (uint64_t)((crc6(A32_flip,8*offset+len)>>26)&0x3f);
} else if (len<=64) {
Ar = (B[0]>>crclen) | (B[1]<<(64-crclen));;
uint8_t A64_flip[8+offset];
if (ones_flag) {
A64_flip[0] = 0xff;
A64_flip[1] = 0xff;
A64_flip[2] = 0xff;
}
uint64_t Aprime= (uint64_t)(Ar<<(64-len));
A64_flip[0+offset]=((uint8_t *)&Aprime)[7];
A64_flip[1+offset]=((uint8_t *)&Aprime)[6];
A64_flip[2+offset]=((uint8_t *)&Aprime)[5];
A64_flip[3+offset]=((uint8_t *)&Aprime)[4];
A64_flip[4+offset]=((uint8_t *)&Aprime)[3];
A64_flip[5+offset]=((uint8_t *)&Aprime)[2];
A64_flip[6+offset]=((uint8_t *)&Aprime)[1];
A64_flip[7+offset]=((uint8_t *)&Aprime)[0];
if (crclen==24) crc = (uint64_t)(crc24c(A64_flip,8*offset+len)>>8)&0xffffff;
else if (crclen==11) crc = (uint64_t)(crc11(A64_flip,8*offset+len)>>21)&0x7ff;
else if (crclen==6) crc = (uint64_t)(crc6(A64_flip,8*offset+len)>>26)&0x3f;
}
#if 0
printf("A %llx B %llx|%llx Cprime %llx|%llx (crc %x,rxcrc %llx %d)\n",
Ar,
B[1],B[0],Cprime[1],Cprime[0],crc,
rxcrc,polarParams->payloadBits);
#endif
out[0]=Ar;
polarReturn crc^rxcrc;
}
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