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sdrangel/plugins/channeltx/moddatv/dvb-s2/dvb2_bch.cpp

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///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com> //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////////
// polymult.cpp : Defines the entry point for the console application.
//
#include "stdio.h"
#include "stdlib.h"
#include "memory.h"
#include "DVBS2.h"
//
// Display routines.
//
void display_poly( int *in, int len )
{
loggerf("\n");
for( int i = 0; i < len; i++ )
{
if(in[i] == 1 )
{
if( i == 0 )
loggerf("1");
else
if( i == 1 )
loggerf("+x");
else
loggerf("+x^%d",i);
}
}
loggerf("\n");
}
//
// length is in bits
//
void display_poly_pack( unsigned int *in, int len )
{
(void) in;
// loggerf("\n");
for( int i = 0; i < len/32; i++ )
{
// loggerf("%.8X",in[i]);
}
switch((len%32)/8)
{
case 0:
break;
case 1:
// loggerf("%.2X",in[(len/32)]>>24);
break;
case 2:
// loggerf("%.2X",in[(len/32)]>>24);
// loggerf("%.2X",in[(len/32)]>>16);
break;
case 3:
// loggerf("%.2X",in[(len/32)]>>24);
// loggerf("%.2X",in[(len/32)]>>16);
// loggerf("%.2X",in[(len/32)]>>8);
break;
}
// loggerf("\n");
}
//
// Polynomial calculation routines
//
// multiply polynomials
//
int DVB2::poly_mult( const int *ina, int lena, const int *inb, int lenb, int *out )
{
memset( out, 0, sizeof(int)*(lena+lenb));
for( int i = 0; i < lena; i++ )
{
for( int j = 0; j < lenb; j++ )
{
if( ina[i]*inb[j] > 0 ) out[i+j]++;// count number of terms for this pwr of x
}
}
int max=0;
for( int i = 0; i < lena+lenb; i++ )
{
out[i] = out[i]&1;// If even ignore the term
if(out[i]) max = i;
}
// return the size of array to house the result.
return max+1;
}
//
// Pack the polynomial into a 32 bit array
//
void DVB2::poly_pack( const int *pin, u32* pout, int len )
{
int lw = len/32;
int ptr = 0;
u32 temp;
if( len % 32 ) lw++;
for( int i = 0; i < lw; i++ )
{
temp = 0x80000000;
pout[i] = 0;
for( int j = 0; j < 32; j++ )
{
if( pin[ptr++] ) pout[i] |= temp;
temp >>= 1;
}
}
}
void DVB2::poly_reverse( int *pin, int *pout, int len )
{
int c;
c = len-1;
for( int i = 0; i < len; i++ )
{
pout[c--] = pin[i];
}
}
//
// Shift a 128 bit register
//
void inline DVB2::reg_4_shift( u32 *sr )
{
sr[3] = (sr[3]>>1) | (sr[2]<<31);
sr[2] = (sr[2]>>1) | (sr[1]<<31);
sr[1] = (sr[1]>>1) | (sr[0]<<31);
sr[0] = (sr[0]>>1);
}
//
// Shift 160 bits
//
void inline DVB2::reg_5_shift( u32 *sr )
{
sr[4] = (sr[4]>>1) | (sr[3]<<31);
sr[3] = (sr[3]>>1) | (sr[2]<<31);
sr[2] = (sr[2]>>1) | (sr[1]<<31);
sr[1] = (sr[1]>>1) | (sr[0]<<31);
sr[0] = (sr[0]>>1);
}
//
// Shift 192 bits
//
void inline DVB2::reg_6_shift( u32 *sr )
{
sr[5] = (sr[5]>>1) | (sr[4]<<31);
sr[4] = (sr[4]>>1) | (sr[3]<<31);
sr[3] = (sr[3]>>1) | (sr[2]<<31);
sr[2] = (sr[2]>>1) | (sr[1]<<31);
sr[1] = (sr[1]>>1) | (sr[0]<<31);
sr[0] = (sr[0]>>1);
}
//
// Take an bit array, bch encode it and place the result in a bit array
// The input length is in bits.
//
Bit DVB2::bch_n_8_encode( Bit *in, int len )
{
Bit b;
int i;
u32 shift[4];
//Zero the shift register
memset( shift,0,sizeof(u32)*4);
for( i = 0; i < len; i++ )
{
b = in[i]^(shift[3]&1);
reg_4_shift( shift );
if( b )
{
shift[0] ^= m_poly_n_8[0];
shift[1] ^= m_poly_n_8[1];
shift[2] ^= m_poly_n_8[2];
shift[3] ^= m_poly_n_8[3];
}
}
// Now add the parity bits to the output
for( int n = 0; n < 128; n++ )
{
in[i++] = shift[3]&1;
reg_4_shift( shift );
}
return i;
}
Bit DVB2::bch_n_10_encode( Bit *in,int len )
{
Bit b;
int i;
u32 shift[5];
//Zero the shift register
memset( shift,0,sizeof(u32)*5);
for( i = 0; i < len; i++ )
{
b = in[i]^(shift[4]&1);
reg_5_shift( shift );
if(b)
{
shift[0] ^= m_poly_n_10[0];
shift[1] ^= m_poly_n_10[1];
shift[2] ^= m_poly_n_10[2];
shift[3] ^= m_poly_n_10[3];
shift[4] ^= m_poly_n_10[4];
}
}
// Now add the parity bits to the output
for( int n = 0; n < 160; n++ )
{
in[i++] = shift[4]&1;
reg_5_shift( shift );
}
return i;
}
Bit DVB2::bch_n_12_encode( Bit *in, int len )
{
Bit b;
int i;
u32 shift[6];
//Zero the shift register
memset( shift,0,sizeof(u32)*6);
// MSB of the codeword first
for( i = 0; i < len; i++ )
{
b = in[i] ^ (shift[5]&1);
reg_6_shift( shift );
if(b)
{
shift[0] ^= m_poly_n_12[0];
shift[1] ^= m_poly_n_12[1];
shift[2] ^= m_poly_n_12[2];
shift[3] ^= m_poly_n_12[3];
shift[4] ^= m_poly_n_12[4];
shift[5] ^= m_poly_n_12[5];
}
}
// Now add the parity bits to the output
for( int n = 0; n < 192; n++ )
{
in[i++] = shift[5]&1;
reg_6_shift( shift );
}
return i;
}
Bit DVB2::bch_s_12_encode( Bit *in, int len )
{
Bit b;
int i;
u32 shift[6];
//Zero the shift register
memset( shift,0,sizeof(u32)*6);
for( i = 0; i < len; i++ )
{
b = (in[i] ^ ((shift[5]&0x01000000)?1:0));
reg_6_shift( shift );
if(b)
{
shift[0] ^= m_poly_s_12[0];
shift[1] ^= m_poly_s_12[1];
shift[2] ^= m_poly_s_12[2];
shift[3] ^= m_poly_s_12[3];
shift[4] ^= m_poly_s_12[4];
shift[5] ^= m_poly_s_12[5];
}
}
// Now add the parity bits to the output
for( int n = 0; n < 168; n++ )
{
in[i++] = (shift[5]&0x01000000) ? 1:0;
reg_6_shift( shift );
}
return i;
}
int DVB2::bch_encode( void )
{
int res;
int len = m_format[0].kbch;
switch(m_format[0].bch_code)
{
case BCH_CODE_N8:
res = bch_n_8_encode( m_frame, len );
break;
case BCH_CODE_N10:
res = bch_n_10_encode( m_frame, len );
break;
case BCH_CODE_N12:
res = bch_n_12_encode( m_frame, len );
break;
case BCH_CODE_S12:
res = bch_s_12_encode( m_frame, len );
break;
default:
printf("BCH error situation\n");
res = 0;
break;
}
return res;
}
//
//
//
void DVB2::bch_poly_build_tables( void )
{
// Normal polynomials
const int polyn01[]={1,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,1};
const int polyn02[]={1,1,0,0,1,1,1,0,1,0,0,0,0,0,0,0,1};
const int polyn03[]={1,0,1,1,1,1,0,1,1,1,1,1,0,0,0,0,1};
const int polyn04[]={1,0,1,0,1,0,1,0,0,1,0,1,1,0,1,0,1};
const int polyn05[]={1,1,1,1,0,1,0,0,1,1,1,1,1,0,0,0,1};
const int polyn06[]={1,0,1,0,1,1,0,1,1,1,1,0,1,1,1,1,1};
const int polyn07[]={1,0,1,0,0,1,1,0,1,1,1,1,0,1,0,1,1};
const int polyn08[]={1,1,1,0,0,1,1,0,1,1,0,0,1,1,1,0,1};
const int polyn09[]={1,0,0,0,0,1,0,1,0,1,1,1,0,0,0,0,1};
const int polyn10[]={1,1,1,0,0,1,0,1,1,0,1,0,1,1,1,0,1};
const int polyn11[]={1,0,1,1,0,1,0,0,0,1,0,1,1,1,0,0,1};
const int polyn12[]={1,1,0,0,0,1,1,1,0,1,0,1,1,0,0,0,1};
// Short polynomials
const int polys01[]={1,1,0,1,0,1,0,0,0,0,0,0,0,0,1};
const int polys02[]={1,0,0,0,0,0,1,0,1,0,0,1,0,0,1};
const int polys03[]={1,1,1,0,0,0,1,0,0,1,1,0,0,0,1};
const int polys04[]={1,0,0,0,1,0,0,1,1,0,1,0,1,0,1};
const int polys05[]={1,0,1,0,1,0,1,0,1,1,0,1,0,1,1};
const int polys06[]={1,0,0,1,0,0,0,1,1,1,0,0,0,1,1};
const int polys07[]={1,0,1,0,0,1,1,1,0,0,1,1,0,1,1};
const int polys08[]={1,0,0,0,0,1,0,0,1,1,1,1,0,0,1};
const int polys09[]={1,1,1,1,0,0,0,0,0,1,1,0,0,0,1};
const int polys10[]={1,0,0,1,0,0,1,0,0,1,0,1,1,0,1};
const int polys11[]={1,0,0,0,1,0,0,0,0,0,0,1,1,0,1};
const int polys12[]={1,1,1,1,0,1,1,1,1,0,1,0,0,1,1};
int len;
int polyout[3][2000];
len = poly_mult( polyn01, 17, polyn02, 17, polyout[0] );
len = poly_mult( polyn03, 17, polyout[0], len, polyout[1] );
len = poly_mult( polyn04, 17, polyout[1], len, polyout[0] );
len = poly_mult( polyn05, 17, polyout[0], len, polyout[1] );
len = poly_mult( polyn06, 17, polyout[1], len, polyout[0] );
len = poly_mult( polyn07, 17, polyout[0], len, polyout[1] );
len = poly_mult( polyn08, 17, polyout[1], len, polyout[0] );
poly_pack( polyout[0], m_poly_n_8, 128 );
// display_poly_pack( m_poly_n_8, 128);
len = poly_mult( polyn09, 17, polyout[0], len, polyout[1] );
len = poly_mult( polyn10, 17, polyout[1], len, polyout[0] );
poly_pack( polyout[0], m_poly_n_10, 160 );
// display_poly_pack( m_poly_n_10, 160);
len = poly_mult( polyn11, 17, polyout[0], len, polyout[1] );
len = poly_mult( polyn12, 17, polyout[1], len, polyout[0] );
poly_pack( polyout[0], m_poly_n_12, 192 );
// display_poly_pack( m_poly_n_12, 192);
// display_poly( polyout[0], len );//12
len = poly_mult( polys01, 15, polys02, 15, polyout[0] );
len = poly_mult( polys03, 15, polyout[0], len, polyout[1] );
len = poly_mult( polys04, 15, polyout[1], len, polyout[0] );
len = poly_mult( polys05, 15, polyout[0], len, polyout[1] );
len = poly_mult( polys06, 15, polyout[1], len, polyout[0] );
len = poly_mult( polys07, 15, polyout[0], len, polyout[1] );
len = poly_mult( polys08, 15, polyout[1], len, polyout[0] );
len = poly_mult( polys09, 15, polyout[0], len, polyout[1] );
len = poly_mult( polys10, 15, polyout[1], len, polyout[0] );
len = poly_mult( polys11, 15, polyout[0], len, polyout[1] );
len = poly_mult( polys12, 15, polyout[1], len, polyout[0] );
poly_pack( polyout[0], m_poly_s_12, 168 );
// display_poly_pack( m_poly_s_12, 168);
/*
// test
int pt1[] = {1,1};
int pt2[] = {1,1,1};
int pt3[] = {1,0,1,1,1,1};
len = poly_mult( pt1, 2, pt2, 3, polyout[0] );
len = poly_mult( pt3, 6, polyout[0], len, polyout[1] );
display_poly( polyout[1], len );
poly_pack( polyout[1], m_poly_s_12, len );
display_poly_pack( m_poly_s_12, 8 );
u32 shift[6];
shift[0] = 0x80000000;
shift[1] = 0x00000000;
shift[2] = 0x00000000;
shift[3] = 0x00000000;
shift[4] = 0x00000000;
shift[5] = 0x00000000;
for( int i = 0; i < 192; i++ )
{
display_poly_pack( shift, 192 );
reg_6_shift( shift );
}
// display_poly( polyout[0], len );//12
// display_poly_pack( m_poly_s_12, 168 );// Wont work because of shift register length
*/
}
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