mirror of
https://github.com/dj0abr/SSB_HighSpeed_Modem.git
synced 2024-10-31 15:37:12 -04:00
208 lines
5.8 KiB
C++
208 lines
5.8 KiB
C++
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/*
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* High Speed modem to transfer data in a 2,7kHz SSB channel
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* =========================================================
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* Author: DJ0ABR
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*
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* (c) DJ0ABR
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* www.dj0abr.de
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include "hsmodem.h"
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// functions for non-differential QPSK
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// depending on the phase shift rotate a data blocks constellation
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//uint8_t headerbytes[HEADERLEN] = {0x53, 0xe1, 0xa6};
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// corresponds to these QPSK symbols:
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// bits: 01010011 11100001 10100110
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// syms: 1 1 0 3 3 2 0 1 2 2 1 2
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uint8_t rxbytebuf[UDPBLOCKLEN+100]; // +100 ... reserve, just to be sure
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uint8_t *convertQPSKSymToBytes(uint8_t *rxsymbols)
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{
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int sidx = 0;
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for(int i=0; i<UDPBLOCKLEN; i++)
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{
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rxbytebuf[i] = rxsymbols[sidx++] << (bitsPerSymbol*3);
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rxbytebuf[i] |= rxsymbols[sidx++] << (bitsPerSymbol*2);
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rxbytebuf[i] |= rxsymbols[sidx++] << (bitsPerSymbol*1);
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rxbytebuf[i] |= rxsymbols[sidx++] << (bitsPerSymbol*0);
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}
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return rxbytebuf;
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}
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void convertBytesToSyms_QPSK(uint8_t *bytes, uint8_t *syms, int bytenum)
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{
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unsigned int symidx = 0;
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for(int i=0; i<bytenum; i++)
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{
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syms[symidx++] = (bytes[i] >> 6) & 3;
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syms[symidx++] = (bytes[i] >> 4) & 3;
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syms[symidx++] = (bytes[i] >> 2) & 3;
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syms[symidx++] = (bytes[i] >> 0) & 3;
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}
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}
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void rotateQPSKsyms(uint8_t *src, uint8_t *dst, int len)
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{
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for(int i=0; i<len; i++)
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{
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dst[i] = src[i] + 4;
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dst[i]++;
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dst[i] %= 4;
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}
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}
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uint8_t QPSK_backbuf[UDPBLOCKLEN*8/2];
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uint8_t *rotateBackQPSK(uint8_t *buf, int len, int rotations)
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{
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memcpy(QPSK_backbuf,buf,len);
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for(unsigned int i=0; i<(unsigned int)len; i++)
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{
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for(int r=0; r<rotations; r++)
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{
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QPSK_backbuf[i] += 4;
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QPSK_backbuf[i]--;
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QPSK_backbuf[i] %= 4;
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}
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}
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return QPSK_backbuf;
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}
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// works ONLY if number of bytes is a multiple of 3 !!!
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void convertBytesToSyms_8PSK(uint8_t *bytes, uint8_t *syms, int bytenum)
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{
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unsigned int symidx = 0;
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for(int i=0; i<bytenum; i+=3)
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{
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// convert next 3 bytes to 8 syms
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syms[symidx++] = (bytes[0+i] >> 5) & 7;
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syms[symidx++] = (bytes[0+i] >> 2) & 7;
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syms[symidx++] = ((bytes[0+i] & 3) << 1) | ((bytes[1+i] >> 7) & 1);
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syms[symidx++] = (bytes[1+i] >> 4) & 7;
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syms[symidx++] = (bytes[1+i] >> 1) & 7;
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syms[symidx++] = ((bytes[1+i] & 1) << 2) | ((bytes[2+i] >> 6) & 3);
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syms[symidx++] = (bytes[2+i] >> 3) & 7;
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syms[symidx++] = bytes[2+i] & 7;
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}
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}
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void rotate8PSKsyms(uint8_t *src, uint8_t *dst, int len)
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{
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for(int i=0; i<len; i++)
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{
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dst[i] = src[i] + 8;
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dst[i]++;
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dst[i] %= 8;
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}
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}
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void rotate8APSKsyms(uint8_t *src, uint8_t *dst, int len)
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{
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for(int i=0; i<len; i++)
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{
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if(src[i] == 0) dst[i] = 0;
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else if(src[i] == 1) dst[i] = 4;
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else if(src[i] == 2) dst[i] = 3;
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else if(src[i] == 3) dst[i] = 1;
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else if(src[i] == 4) dst[i] = 5;
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else if(src[i] == 5) dst[i] = 7;
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else if(src[i] == 6) dst[i] = 2;
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else if(src[i] == 7) dst[i] = 6;
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}
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}
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uint8_t _8PSK_backbuf[UDPBLOCKLEN*8/3];
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uint8_t *rotateBack8PSK(uint8_t *buf, int len, int rotations)
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{
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memcpy(_8PSK_backbuf,buf,len);
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for(int i=0; i<len; i++)
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{
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for(int r=0; r<rotations; r++)
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{
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_8PSK_backbuf[i] += 8;
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_8PSK_backbuf[i]--;
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_8PSK_backbuf[i] %= 8;
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}
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}
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return _8PSK_backbuf;
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}
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uint8_t *rotateBack8APSK(uint8_t *buf, int len, int rotations)
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{
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memcpy(_8PSK_backbuf,buf,len);
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for(int i=0; i<len; i++)
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{
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for(int r=0; r<rotations; r++)
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{
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if(_8PSK_backbuf[i] == 0) _8PSK_backbuf[i] = 0;
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else if(_8PSK_backbuf[i] == 4) _8PSK_backbuf[i] = 1;
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else if(_8PSK_backbuf[i] == 3) _8PSK_backbuf[i] = 2;
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else if(_8PSK_backbuf[i] == 1) _8PSK_backbuf[i] = 3;
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else if(_8PSK_backbuf[i] == 5) _8PSK_backbuf[i] = 4;
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else if(_8PSK_backbuf[i] == 7) _8PSK_backbuf[i] = 5;
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else if(_8PSK_backbuf[i] == 2) _8PSK_backbuf[i] = 6;
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else if(_8PSK_backbuf[i] == 6) _8PSK_backbuf[i] = 7;
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}
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}
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return _8PSK_backbuf;
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}
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uint8_t *convert8PSKSymToBytes(uint8_t *rxsymbols, int len)
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{
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int sidx = 0;
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// works ONLY if total frame length is a multiple of 3 !
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for(int i=0; i<len; i+=3)
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{
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rxbytebuf[i] = rxsymbols[sidx++] << 5;
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rxbytebuf[i] |= rxsymbols[sidx++] << 2;
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rxbytebuf[i] |= rxsymbols[sidx] >> 1;
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rxbytebuf[i+1] = rxsymbols[sidx++] << 7;
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rxbytebuf[i+1] |= rxsymbols[sidx++] << 4;
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rxbytebuf[i+1] |= rxsymbols[sidx++] << 1;
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rxbytebuf[i+1] |= rxsymbols[sidx] >> 2;
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rxbytebuf[i+2] = rxsymbols[sidx++] << 6;
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rxbytebuf[i+2] |= rxsymbols[sidx++] << 3;
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rxbytebuf[i+2] |= rxsymbols[sidx++];
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}
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return rxbytebuf;
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}
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void shiftleft(uint8_t *data, int shiftnum, int len)
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{
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for(int j=0; j<shiftnum; j++)
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{
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int b1=0,b2=0;
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for(int i=len-1; i>=0; i--)
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{
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b1 = (data[i] & 0x80)>>7;
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data[i] <<= 1;
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data[i] |= b2;
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b2 = b1;
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}
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}
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}
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