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d13644773d1603a1518657c8f5fd23a5e8d6bf5c
openairinterface5g/openair1/PHY/CODING/nrPolar_tools/nr_polar_decoding_tools.c
T
laurent d13644773d some critical warnings
2019-03-18 13:30:25 +01:00

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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_decoding_tools.c
* \brief
* \author Turker Yilmaz
* \date 2018
* \version 0.1
* \company EURECOM
* \email turker.yilmaz@eurecom.fr
* \note
* \warning
*/
#include "PHY/CODING/nrPolar_tools/nr_polar_defs.h"
#include "PHY/sse_intrin.h"
#include "PHY/impl_defs_top.h"
//#define DEBUG_NEW_IMPL 1
void updateLLR(double ***llr,
uint8_t **llrU,
uint8_t ***bit,
uint8_t **bitU,
uint8_t listSize,
uint16_t row,
uint16_t col,
uint16_t xlen,
uint8_t ylen,
uint8_t approximation)
{
uint16_t offset = (xlen/(pow(2,(ylen-col-1))));
for (uint8_t i=0; i<listSize; i++) {
if (( (row) % (2*offset) ) >= offset ) {
if(bitU[row-offset][col]==0) updateBit(bit, bitU, listSize, (row-offset), col, xlen, ylen);
if(llrU[row-offset][col+1]==0) updateLLR(llr, llrU, bit, bitU, listSize, (row-offset), (col+1), xlen, ylen, approximation);
if(llrU[row][col+1]==0) updateLLR(llr, llrU, bit, bitU, listSize, row, (col+1), xlen, ylen, approximation);
llr[row][col][i] = (pow((-1),bit[row-offset][col][i])*llr[row-offset][col+1][i]) + llr[row][col+1][i];
} else {
if(llrU[row][col+1]==0) updateLLR(llr, llrU, bit, bitU, listSize, row, (col+1), xlen, ylen, approximation);
if(llrU[row+offset][col+1]==0) updateLLR(llr, llrU, bit, bitU, listSize, (row+offset), (col+1), xlen, ylen, approximation);
computeLLR(llr, row, col, i, offset, approximation);
}
}
llrU[row][col]=1;
// printf("LLR (a %f, b %f): llr[%d][%d] %f\n",32*a,32*b,col,row,32*llr[col][row]);
}
void updateBit(uint8_t ***bit,
uint8_t **bitU,
uint8_t listSize,
uint16_t row,
uint16_t col,
uint16_t xlen,
uint8_t ylen)
{
uint16_t offset = ( xlen/(pow(2,(ylen-col))) );
for (uint8_t i=0; i<listSize; i++) {
if (( (row) % (2*offset) ) >= offset ) {
if (bitU[row][col-1]==0) updateBit(bit, bitU, listSize, row, (col-1), xlen, ylen);
bit[row][col][i] = bit[row][col-1][i];
} else {
if (bitU[row][col-1]==0) updateBit(bit, bitU, listSize, row, (col-1), xlen, ylen);
if (bitU[row+offset][col-1]==0) updateBit(bit, bitU, listSize, (row+offset), (col-1), xlen, ylen);
bit[row][col][i] = ( (bit[row][col-1][i]+bit[row+offset][col-1][i]) % 2);
}
}
bitU[row][col]=1;
}
void updatePathMetric(double *pathMetric,
double ***llr,
uint8_t listSize,
uint8_t bitValue,
uint16_t row,
uint8_t approximation)
{
if (approximation) { //eq. (12)
for (uint8_t i=0; i<listSize; i++) {
if ((2*bitValue) != ( 1 - copysign(1.0,llr[row][0][i]) )) pathMetric[i] += fabs(llr[row][0][i]);
}
} else { //eq. (11b)
int8_t multiplier = (2*bitValue) - 1;
for (uint8_t i=0; i<listSize; i++) pathMetric[i] += log ( 1 + exp(multiplier*llr[row][0][i]) ) ;
}
}
void updatePathMetric2(double *pathMetric,
double ***llr,
uint8_t listSize,
uint16_t row,
uint8_t appr)
{
double *tempPM = malloc(sizeof(double) * listSize);
for (int i=0; i < listSize; i++) tempPM[i]=pathMetric[i];
uint8_t bitValue = 0;
if (appr) { //eq. (12)
for (uint8_t i = 0; i < listSize; i++) {
if ((2 * bitValue) != (1 - copysign(1.0, llr[row][0][i]))) pathMetric[i] += fabs(llr[row][0][i]);
}
} else { //eq. (11b)
int8_t multiplier = (2 * bitValue) - 1;
for (uint8_t i = 0; i < listSize; i++) pathMetric[i] += log(1 + exp(multiplier * llr[row][0][i]));
}
bitValue = 1;
if (appr) { //eq. (12)
for (uint8_t i = listSize; i < 2*listSize; i++) {
if ((2 * bitValue) != (1 - copysign(1.0, llr[row][0][(i-listSize)]))) pathMetric[i] = tempPM[(i-listSize)] + fabs(llr[row][0][(i-listSize)]);
}
} else { //eq. (11b)
int8_t multiplier = (2 * bitValue) - 1;
for (uint8_t i = listSize; i < 2*listSize; i++) pathMetric[i] = tempPM[(i-listSize)] + log(1 + exp(multiplier * llr[row][0][(i-listSize)]));
}
free(tempPM);
}
void computeLLR(double ***llr,
uint16_t row,
uint16_t col,
uint8_t i,
uint16_t offset,
uint8_t approximation)
{
double a = llr[row][col + 1][i];
double absA = fabs(a);
double b = llr[row + offset][col + 1][i];
double absB = fabs(b);
if (approximation || isinf(absA) || isinf(absB)) { //eq. (9)
llr[row][col][i] = copysign(1.0, a) * copysign(1.0, b) * fmin(absA, absB);
} else { //eq. (8a)
llr[row][col][i] = log((exp(a + b) + 1) / (exp(a) + exp(b)));
}
}
void updateCrcChecksum(uint8_t **crcChecksum,
uint8_t **crcGen,
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] = ( (crcChecksum[j][i] + crcGen[i2][j]) % 2 );
}
}
}
void updateCrcChecksum2(uint8_t **crcChecksum,
uint8_t **crcGen,
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 );
}
}
}
decoder_node_t *new_decoder_node(int first_leaf_index,int level) {
decoder_node_t *node=(decoder_node_t *)malloc(sizeof(decoder_node_t));
node->first_leaf_index=first_leaf_index;
node->level=level;
node->Nv = 1<<level;
node->leaf = 0;
node->left=(decoder_node_t *)NULL;
node->right=(decoder_node_t *)NULL;
node->all_frozen=0;
node->alpha = (int16_t*)malloc16(node->Nv*sizeof(int16_t));
node->beta = (int16_t*)malloc16(node->Nv*sizeof(int16_t));
memset((void*)node->beta,-1,node->Nv*sizeof(int16_t));
return(node);
}
decoder_node_t *add_nodes(int level,int first_leaf_index,t_nrPolar_params *pp) {
int all_frozen_below=1;
int Nv = 1<<level;
decoder_node_t *new_node = new_decoder_node(first_leaf_index,level);
#ifdef DEBUG_NEW_IMPL
printf("New node %d order %d, level %d\n",pp->tree.num_nodes,Nv,level);
#endif
pp->tree.num_nodes++;
if (level==0) {
#ifdef DEBUG_NEW_IMPL
printf("leaf %d (%s)\n",first_leaf_index,pp->information_bit_pattern[first_leaf_index]==1 ? "information or crc" : "frozen");
#endif
new_node->leaf=1;
new_node->all_frozen = pp->information_bit_pattern[first_leaf_index]==0 ? 1 : 0;
return new_node; // this is a leaf node
}
for (int i=0;i<Nv;i++) {
if (pp->information_bit_pattern[i+first_leaf_index]>0) all_frozen_below=0;
}
if (all_frozen_below==0) new_node->left=add_nodes(level-1,first_leaf_index,pp);
else {
#ifdef DEBUG_NEW_IMPL
printf("aggregating frozen bits %d ... %d at level %d (%s)\n",first_leaf_index,first_leaf_index+Nv-1,level,((first_leaf_index/Nv)&1)==0?"left":"right");
#endif
new_node->leaf=1;
new_node->all_frozen=1;
}
if (all_frozen_below==0) new_node->right=add_nodes(level-1,first_leaf_index+(Nv/2),pp);
#ifdef DEBUG_NEW_IMPL
printf("new_node (%d): first_leaf_index %d, left %p, right %p\n",Nv,first_leaf_index,new_node->left,new_node->right);
#endif
return(new_node);
}
void build_decoder_tree(t_nrPolar_params *pp) {
pp->tree.num_nodes=0;
pp->tree.root = add_nodes(pp->n,0,pp);
#ifdef DEBUG_NEW_IMPL
printf("root : left %p, right %p\n",pp->tree.root->left,pp->tree.root->right);
#endif
}
#if defined(__arm__) || defined(__aarch64__)
// translate 1-1 SIMD functions from SSE to NEON
#define __m128i int16x8_t
#define __m64 int8x8_t
#define _mm_abs_epi16(a) vabsq_s16(a)
#define _mm_min_epi16(a,b) vminq_s16(a,b)
#define _mm_subs_epi16(a,b) vsubq_s16(a,b)
#define _mm_abs_pi16(a) vabs_s16(a)
#define _mm_min_pi16(a,b) vmin_s16(a,b)
#define _mm_subs_pi16(a,b) vsub_s16(a,b)
#endif
void applyFtoleft(t_nrPolar_params *pp,decoder_node_t *node) {
int16_t *alpha_v=node->alpha;
int16_t *alpha_l=node->left->alpha;
int16_t *betal = node->left->beta;
int16_t a,b,absa,absb,maska,maskb,minabs;
#ifdef DEBUG_NEW_IMPL
printf("applyFtoleft %d, Nv %d (level %d,node->left (leaf %d, AF %d))\n",node->first_leaf_index,node->Nv,node->level,node->left->leaf,node->left->all_frozen);
for (int i=0;i<node->Nv;i++) printf("i%d (frozen %d): alpha_v[i] = %d\n",i,1-pp->information_bit_pattern[node->first_leaf_index+i],alpha_v[i]);
#endif
if (node->left->all_frozen == 0) {
#if defined(__AVX2__)
int avx2mod = (node->Nv/2)&15;
if (avx2mod == 0) {
__m256i a256,b256,absa256,absb256,minabs256;
int avx2len = node->Nv/2/16;
// printf("avx2len %d\n",avx2len);
for (int i=0;i<avx2len;i++) {
a256 =((__m256i*)alpha_v)[i];
b256 =((__m256i*)alpha_v)[i+avx2len];
absa256 =_mm256_abs_epi16(a256);
absb256 =_mm256_abs_epi16(b256);
minabs256 =_mm256_min_epi16(absa256,absb256);
((__m256i*)alpha_l)[i] =_mm256_sign_epi16(minabs256,_mm256_sign_epi16(a256,b256));
}
}
else if (avx2mod == 8) {
__m128i a128,b128,absa128,absb128,minabs128;
a128 =*((__m128i*)alpha_v);
b128 =((__m128i*)alpha_v)[1];
absa128 =_mm_abs_epi16(a128);
absb128 =_mm_abs_epi16(b128);
minabs128 =_mm_min_epi16(absa128,absb128);
*((__m128i*)alpha_l) =_mm_sign_epi16(minabs128,_mm_sign_epi16(a128,b128));
}
else if (avx2mod == 4) {
__m64 a64,b64,absa64,absb64,minabs64;
a64 =*((__m64*)alpha_v);
b64 =((__m64*)alpha_v)[1];
absa64 =_mm_abs_pi16(a64);
absb64 =_mm_abs_pi16(b64);
minabs64 =_mm_min_pi16(absa64,absb64);
*((__m64*)alpha_l) =_mm_sign_pi16(minabs64,_mm_sign_pi16(a64,b64));
}
else
#else
int sse4mod = (node->Nv/2)&7;
int sse4len = node->Nv/2/8;
#if defined(__arm__) || defined(__aarch64__)
int16x8_t signatimesb,comp1,comp2,negminabs128;
int16x8_t zero=vdupq_n_s16(0);
#endif
if (sse4mod == 0) {
for (int i=0;i<sse4len;i++) {
__m128i a128,b128,absa128,absb128,minabs128;
int sse4len = node->Nv/2/8;
a128 =*((__m128i*)alpha_v);
b128 =((__m128i*)alpha_v)[1];
absa128 =_mm_abs_epi16(a128);
absb128 =_mm_abs_epi16(b128);
minabs128 =_mm_min_epi16(absa128,absb128);
#if defined(__arm__) || defined(__aarch64__)
// unfortunately no direct equivalent to _mm_sign_epi16
signatimesb=vxorrq_s16(a128,b128);
comp1=vcltq_s16(signatimesb,zero);
comp2=vcgeq_s16(signatimesb,zero);
negminabs128=vnegq_s16(minabs128);
*((__m128i*)alpha_l) =vorrq_s16(vandq_s16(minabs128,comp0),vandq_s16(negminabs128,comp1));
#else
*((__m128i*)alpha_l) =_mm_sign_epi16(minabs128,_mm_sign_epi16(a128,b128));
#endif
}
}
else if (sse4mod == 4) {
__m64 a64,b64,absa64,absb64,minabs64;
a64 =*((__m64*)alpha_v);
b64 =((__m64*)alpha_v)[1];
absa64 =_mm_abs_pi16(a64);
absb64 =_mm_abs_pi16(b64);
minabs64 =_mm_min_pi16(absa64,absb64);
#if defined(__arm__) || defined(__aarch64__)
AssertFatal(1==0,"Need to do this still for ARM\n");
#else
*((__m64*)alpha_l) =_mm_sign_pi16(minabs64,_mm_sign_epi16(a64,b64));
#endif
}
else
#endif
{ // equvalent scalar code to above, activated only on non x86/ARM architectures
for (int i=0;i<node->Nv/2;i++) {
a=alpha_v[i];
b=alpha_v[i+(node->Nv/2)];
maska=a>>15;
maskb=b>>15;
absa=(a+maska)^maska;
absb=(b+maskb)^maskb;
minabs = absa<absb ? absa : absb;
alpha_l[i] = (maska^maskb)==0 ? minabs : -minabs;
// printf("alphal[%d] %d (%d,%d)\n",i,alpha_l[i],a,b);
}
}
if (node->Nv == 2) { // apply hard decision on left node
betal[0] = (alpha_l[0]>0) ? -1 : 1;
#ifdef DEBUG_NEW_IMPL
printf("betal[0] %d (%p)\n",betal[0],&betal[0]);
#endif
pp->nr_polar_U[node->first_leaf_index] = (1+betal[0])>>1;
#ifdef DEBUG_NEW_IMPL
printf("Setting bit %d to %d (LLR %d)\n",node->first_leaf_index,(betal[0]+1)>>1,alpha_l[0]);
#endif
}
}
}
void applyGtoright(t_nrPolar_params *pp,decoder_node_t *node) {
int16_t *alpha_v=node->alpha;
int16_t *alpha_r=node->right->alpha;
int16_t *betal = node->left->beta;
int16_t *betar = node->right->beta;
#ifdef DEBUG_NEW_IMPL
printf("applyGtoright %d, Nv %d (level %d), (leaf %d, AF %d)\n",node->first_leaf_index,node->Nv,node->level,node->right->leaf,node->right->all_frozen);
#endif
if (node->right->all_frozen == 0) {
#if defined(__AVX2__)
int avx2mod = (node->Nv/2)&15;
if (avx2mod == 0) {
int avx2len = node->Nv/2/16;
for (int i=0;i<avx2len;i++) {
((__m256i *)alpha_r)[i] =
_mm256_subs_epi16(((__m256i *)alpha_v)[i+avx2len],
_mm256_sign_epi16(((__m256i *)alpha_v)[i],
((__m256i *)betal)[i]));
}
}
else if (avx2mod == 8) {
((__m128i *)alpha_r)[0] = _mm_subs_epi16(((__m128i *)alpha_v)[1],_mm_sign_epi16(((__m128i *)alpha_v)[0],((__m128i *)betal)[0]));
}
else if (avx2mod == 4) {
((__m64 *)alpha_r)[0] = _mm_subs_pi16(((__m64 *)alpha_v)[1],_mm_sign_pi16(((__m64 *)alpha_v)[0],((__m64 *)betal)[0]));
}
else
#else
int sse4mod = (node->Nv/2)&7;
if (sse4mod == 0) {
int sse4len = node->Nv/2/8;
for (int i=0;i<sse4len;i++) {
#if defined(__arm__) || defined(__aarch64__)
((int16x8_t *)alpha_r)[0] = vsubq_s16(((int16x8_t *)alpha_v)[1],vmulq_epi16(((int16x8_t *)alpha_v)[0],((int16x8_t *)betal)[0]));
#else
((__m128i *)alpha_r)[0] = _mm_subs_epi16(((__m128i *)alpha_v)[1],_mm_sign_epi16(((__m128i *)alpha_v)[0],((__m128i *)betal)[0]));
#endif
}
}
else if (sse4mod == 4) {
#if defined(__arm__) || defined(__aarch64__)
((int16x4_t *)alpha_r)[0] = vsub_s16(((int16x4_t *)alpha_v)[1],vmul_epi16(((int16x4_t *)alpha_v)[0],((int16x4_t *)betal)[0]));
#else
((__m64 *)alpha_r)[0] = _mm_subs_pi16(((__m64 *)alpha_v)[1],_mm_sign_pi16(((__64 *)alpha_v)[0],((__m64 *)betal)[0]));
#endif
}
else
#endif
{// equvalent scalar code to above, activated only on non x86/ARM architectures or Nv=1,2
for (int i=0;i<node->Nv/2;i++) {
alpha_r[i] = alpha_v[i+(node->Nv/2)] - (betal[i]*alpha_v[i]);
}
}
if (node->Nv == 2) { // apply hard decision on right node
betar[0] = (alpha_r[0]>0) ? -1 : 1;
pp->nr_polar_U[node->first_leaf_index+1] = (1+betar[0])>>1;
#ifdef DEBUG_NEW_IMPL
printf("Setting bit %d to %d (LLR %d)\n",node->first_leaf_index+1,(betar[0]+1)>>1,alpha_r[0]);
#endif
}
}
}
int16_t all1[16] = {1,1,1,1,
1,1,1,1,
1,1,1,1,
1,1,1,1};
void computeBeta(t_nrPolar_params *pp,decoder_node_t *node) {
int16_t *betav = node->beta;
int16_t *betal = node->left->beta;
int16_t *betar = node->right->beta;
#ifdef DEBUG_NEW_IMPL
printf("Computing beta @ level %d first_leaf_index %d (all_frozen %d)\n",node->level,node->first_leaf_index,node->left->all_frozen);
#endif
if (node->left->all_frozen==0) { // if left node is not aggregation of frozen bits
#if defined(__AVX2__)
int avx2mod = (node->Nv/2)&15;
register __m256i allones=*((__m256i*)all1);
if (avx2mod == 0) {
int avx2len = node->Nv/2/16;
for (int i=0;i<avx2len;i++) {
((__m256i*)betav)[i] = _mm256_or_si256(_mm256_cmpeq_epi16(((__m256i*)betar)[i],
((__m256i*)betal)[i]),allones);
}
}
else if (avx2mod == 8) {
((__m128i*)betav)[0] = _mm_or_si128(_mm_cmpeq_epi16(((__m128i*)betar)[0],
((__m128i*)betal)[0]),*((__m128i*)all1));
}
else if (avx2mod == 4) {
((__m64*)betav)[0] = _mm_or_si64(_mm_cmpeq_pi16(((__m64*)betar)[0],
((__m64*)betal)[0]),*((__m64*)all1));
}
else
#else
int avx2mod = (node->Nv/2)&15;
if (ssr4mod == 0) {
int ssr4len = node->Nv/2/8;
register __m128i allones=*((__m128i*)all1);
for (int i=0;i<sse4len;i++) {
((__m256i*)betav)[i] = _mm_or_si128(_mm_cmpeq_epi16(((__m128i*)betar)[i],
((__m128i*)betal)[i]),allones));
}
}
else if (sse4mod == 4) {
((__m64*)betav)[0] = _mm_or_si64(_mm_cmpeq_pi16(((__m64*)betar)[0],
((__m64*)betal)[0]),*((__m64*)all1));
}
else
#endif
{
for (int i=0;i<node->Nv/2;i++) {
betav[i] = (betal[i] != betar[i]) ? 1 : -1;
}
}
}
else memcpy((void*)&betav[0],betar,(node->Nv/2)*sizeof(int16_t));
memcpy((void*)&betav[node->Nv/2],betar,(node->Nv/2)*sizeof(int16_t));
}
void generic_polar_decoder(const t_nrPolar_params *pp,decoder_node_t *node) {
// Apply F to left
applyFtoleft(pp,node);
// if left is not a leaf recurse down to the left
if (node->left->leaf==0) generic_polar_decoder(pp,node->left);
applyGtoright(pp,node);
if (node->right->leaf==0) generic_polar_decoder(pp,node->right);
computeBeta(pp,node);
}
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