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Code CRC Reshaped to libLTE format

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This commit is contained in:
agelonch 2014-05-13 13:31:08 +02:00
parent 07528df864
commit 7e21282dec
4 changed files with 90 additions and 74 deletions
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30
lte/include/lte/fec/crc.h
View file

@ -36,8 +36,34 @@
#define LTE_CRC8 0x19B
int init_crc(int lorder, unsigned long polynom);
#define _WITHMALLOC
#ifndef _WITHMALLOC
#define MAX_LENGTH 1024*16
#endif
typedef struct {
unsigned long table[256];
#ifdef _WITHMALLOC
unsigned char *data0;
#else
unsigned char data0[MAX_LENGTH];
#endif
int polynom;
int order;
unsigned long crcinit;
unsigned long crcxor;
unsigned long crcmask;
unsigned long crchighbit;
unsigned int crc_out;
} crc_t;
//ELIMINATE////////////////////
unsigned int crc(unsigned int crc, char *bufptr, int len,
int long_crc,unsigned int poly, int paste_word);
int long_crc, unsigned int poly, int paste_word);
///////////////////////////////
int crc_init(crc_t *crc_par);
unsigned int crc_attach(char *bufptr, int len, crc_t *crc_params);
#endif

117
lte/lib/fec/src/crc.c
View file

@ -31,116 +31,103 @@
#include <string.h>
#include "lte/utils/pack.h"
#define _WITHMALLOC
unsigned int cword;
char *cdata;
const unsigned long crcinit = 0x00000000; //initial CRC value
const unsigned long crcxor = 0x00000000; //final XOR value
unsigned long crcmask;
unsigned long crchighbit;
unsigned long crctab[256];
#include "lte/fec/crc.h"
void gen_crc_table(crc_t *crc_params) {
void gen_crc_table(int lorder, unsigned long poly) {
int i, j, ord=(lorder-8);
int i, j, ord=(crc_params->order-8);
unsigned long bit, crc;
for (i=0; i<256; i++) {
crc = ((unsigned long)i)<<ord;
for (j=0; j<8; j++) {
bit = crc & crchighbit;
bit = crc & crc_params->crchighbit;
crc<<= 1;
if (bit) crc^= poly;
if (bit) crc^= crc_params->polynom;
}
crctab[i] = crc & crcmask;
crc_params->table[i]=crc & crc_params->crcmask;
}
}
unsigned long crctable (unsigned char* data, unsigned long length, int lorder) {
unsigned long crctable (unsigned long length, crc_t *crc_params) {
// Polynom lorders of 8, 16, 24 or 32.
unsigned long crc = crcinit;
// Polynom order 8, 16, 24 or 32 only.
int ord=crc_params->order-8;
unsigned long crc = crc_params->crcinit;
unsigned char* data = crc_params->data0;
while (length--) crc = (crc << 8) ^ crctab[ ((crc >> (lorder-8)) & 0xff) ^ *data++];
return((crc^crcxor)&crcmask);
while (length--){
crc = (crc << 8) ^ crc_params->table[ ((crc >> (ord)) & 0xff) ^ *data++];
}
return((crc ^ crc_params->crcxor) & crc_params->crcmask);
}
unsigned long reversecrcbit(unsigned int crc, unsigned int polynom, int lorder, int nbits) {
unsigned long reversecrcbit(unsigned int crc, int nbits, crc_t *crc_params) {
unsigned long m, rmask=0x1;
for(m=0; m<nbits; m++){
if((rmask & crc) == 0x01 )crc = (crc ^ polynom)>>1;
if((rmask & crc) == 0x01 )crc = (crc ^ crc_params->polynom)>>1;
else crc = crc >> 1;
}
return((crc^crcxor)&crcmask);
return((crc ^ crc_params->crcxor) & crc_params->crcmask);
}
int init_crc(int lorder, unsigned long polynom){
unsigned long polyhighbit;
int crc_init(crc_t *crc_par){
// Compute bit masks for whole CRC and CRC high bit
crcmask = ((((unsigned long)1<<(lorder-1))-1)<<1)|1;
polyhighbit=0xFFFFFFFF ^ (crcmask+1);
crchighbit = (unsigned long)1<<(lorder-1);
crc_par->crcmask = ((((unsigned long)1<<(crc_par->order-1))-1)<<1)|1;
crc_par->crchighbit = (unsigned long)1<<(crc_par->order-1);
// Eliminate highest bit in polynom word
polynom=polynom & polyhighbit;
printf("crcmask=%x, crchightbit=%x\n",
(unsigned int)crc_par->crcmask, (unsigned int)crc_par->crchighbit);
// check parameters
if (lorder < 1 || lorder > 32) {
printf("ERROR, invalid order, it must be between 1..32.\n");
if (crc_par->order%8 != 0) {
printf("ERROR, invalid order=%d, it must be 8, 16, 24 or 32.\n", crc_par->order);
return(0);
}
if (lorder%8 != 0) {
printf("ERROR, invalid order=%d, it must be 8, 16, 24 or 32.\n", lorder);
return(0);
}
if (polynom != (polynom & crcmask)) {
printf("ERROR, invalid polynom.\n");
return(0);
}
if (crcinit != (crcinit & crcmask)) {
if (crc_par->crcinit != (crc_par->crcinit & crc_par->crcmask)) {
printf("ERROR, invalid crcinit.\n");
return(0);
}
if (crcxor != (crcxor & crcmask)) {
if (crc_par->crcxor != (crc_par->crcxor & crc_par->crcmask)) {
printf("ERROR, invalid crcxor.\n");
return(0);
}
// generate lookup table
gen_crc_table(lorder, polynom);
gen_crc_table(crc_par);
return(1);
}
#define MAX_LENGTH 8192
///ELIMINATE//////////////////////////
unsigned int crc(unsigned int crc, char *bufptr, int len,
int long_crc, unsigned int poly, int paste_word) {
int long_crc, unsigned int poly, int paste_word){
return(0);
}
///////////////////////////////////////
unsigned int crc_attach(char *bufptr, int len, crc_t *crc_params) {
int i, len8, res8, a;
#ifdef _WITHMALLOC
char *data0, *pter;
unsigned int crc;
char *pter;
data0 = (char *)malloc(sizeof(char) * (len+long_crc)*2);
if (!data0) {
#ifdef _WITHMALLOC
crc_params->data0 = (unsigned char *)malloc(sizeof(*crc_params->data0) * (len+crc_params->order)*2);
if (!crc_params->data0) {
perror("malloc ERROR: Allocating memory for data pointer in crc() function");
return(-1);
}
#endif
#ifndef _WITHMALLOC
char data0[MAX_LENGTH], *pter;
if((((len+long_crc)>>3) + 1) > MAX_LENGTH){
#else
if((((len+crc_params->order)>>3) + 1) > MAX_LENGTH){
printf("ERROR: Not enough memory allocated\n");
return(-1);
}
@ -156,24 +143,22 @@ unsigned int crc(unsigned int crc, char *bufptr, int len,
for(i=0; i<len8+a; i++){
pter=(char *)(bufptr+8*i);
data0[i]=(char)(unpack_bits(&pter, 8)&0xFF);
crc_params->data0[i]=(unsigned char)(unpack_bits(&pter, 8)&0xFF);
}
// Calculate CRC
pter=data0;
crc=crctable ((unsigned char *)pter, len8+a, long_crc);
crc=crctable(len8+a, crc_params);
// Reverse CRC res8 positions
if(a==1)crc=reversecrcbit(crc, poly, long_crc, res8);
if(a==1)crc=reversecrcbit(crc, res8, crc_params);
// Add CRC
pter=(char *)(bufptr+len);
pack_bits(crc, &pter, long_crc);
pack_bits(crc, &pter, crc_params->order);
#ifdef _WITHMALLOC
free(data0);
data0=NULL;
free(crc_params->data0);
crc_params->data0=NULL;
#endif
//Return CRC value
return crc;
}

15
lte/lib/fec/test/crc_test.c
View file

@ -77,6 +77,7 @@ int main(int argc, char **argv) {
int i;
char *data;
unsigned int crc_word, expected_word;
crc_t crc_p;
parse_args(argc, argv);
@ -96,22 +97,24 @@ int main(int argc, char **argv) {
data[i] = rand()%2;
}
//Initialize crc params and tables
if(!init_crc(crc_length, crc_poly))exit(0);
//Initialize CRC params and tables
crc_p.polynom=crc_poly;
crc_p.order=crc_length;
crc_p.crcinit=0x00000000;
crc_p.crcxor=0x00000000;
if(!crc_init(&crc_p))exit(0);
// generate CRC word
crc_word = crc(0, data, num_bits, crc_length, crc_poly, 1);
crc_word = crc_attach(data, num_bits, &crc_p);
// check if result is zero
if (crc(0, data, num_bits + crc_length, crc_length, crc_poly, 0)) {
if (crc_attach(data, num_bits + crc_length, &crc_p)) {
printf("CRC check is non-zero\n");
exit(-1);
}
free(data);
printf("CRC word: 0x%x\n", crc_word);
// check if generated word is as expected
if (get_expected_word(num_bits, crc_length, crc_poly, seed, &expected_word)) {
fprintf(stderr, "Test parameters not defined in test_results.h\n");

2
lte/lib/fec/test/crc_test.h
View file

@ -39,11 +39,13 @@ typedef struct {
static expected_word_t expected_words[] = {
//ELIMINATE///////////
/* {5000, 24, LTE_CRC24A, 1, 0x4D0836}, // LTE CRC24A (36.212 Sec 5.1.1)
{5000, 24, LTE_CRC24B, 1, 0x9B68F8}, // LTE CRC24B
{5000, 16, LTE_CRC16, 1, 0xBFFA}, // LTE CRC16: 0xBFFA
{5000, 8, LTE_CRC8, 1, 0xF8}, // LTE CRC8 0xF8
*/
//////////////////////
{5001, 24, LTE_CRC24A, 1, 0x1C5C97}, // LTE CRC24A (36.212 Sec 5.1.1)
{5001, 24, LTE_CRC24B, 1, 0x36D1F0}, // LTE CRC24B
{5001, 16, LTE_CRC16, 1, 0x7FF4}, // LTE CRC16: 0x7FF4