126 lines
2.8 KiB
C++
126 lines
2.8 KiB
C++
#include "StdAfx.h"
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#include "linux/tape.h"
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#include "Core.h"
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#include "Tape.h"
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#include "Memory.h"
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#include "Pravets.h"
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#include "CPU.h"
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#include <limits>
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CassetteTape & CassetteTape::instance()
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{
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static CassetteTape tape;
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return tape;
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}
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void CassetteTape::setData(const std::string & filename, const std::vector<tape_data_t> & data, const int frequency)
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{
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myFilename = filename;
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myData = data;
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myFrequency = frequency;
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myIsPlaying = false;
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}
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void CassetteTape::eject()
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{
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myData.clear();
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}
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void CassetteTape::rewind()
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{
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myIsPlaying = false;
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}
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BYTE CassetteTape::getBitValue(const tape_data_t val)
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{
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// threshold not needed for https://asciiexpress.net
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// but probably necessary for a real audio file
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//
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// this has been tested on all formats from https://asciiexpress.net
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//
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// we are extracting the sign bit (set for negative numbers)
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// this is really important for the asymmetric wave in https://asciiexpress.net/diskserver/
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// not so much for the other cases
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if (val > myThreshold)
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{
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myLastBit = 0;
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}
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else if (val < -myThreshold)
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{
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myLastBit = 1;
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}
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// else leave it unchanged to the previous value
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return myLastBit;
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}
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CassetteTape::tape_data_t CassetteTape::getCurrentWave(size_t & pos) const
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{
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if (myIsPlaying)
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{
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const double delta = g_nCumulativeCycles - myBaseCycles;
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const double position = delta / g_fCurrentCLK6502 * myFrequency;
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pos = static_cast<size_t>(position);
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if (pos + 1 < myData.size())
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{
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// linear interpolation
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const double reminder = position - pos;
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const double value = (1.0 - reminder) * myData[pos] + reminder * myData[pos + 1];
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return lround(value);
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}
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else
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{
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pos = myData.size() - 1;
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}
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}
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else
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{
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pos = 0;
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}
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return std::numeric_limits<tape_data_t>::min();
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}
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BYTE CassetteTape::getValue(const ULONG nExecutedCycles)
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{
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CpuCalcCycles(nExecutedCycles);
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if (!myIsPlaying)
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{
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// start play as soon as TAPEIN is read
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myIsPlaying = true;
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myBaseCycles = g_nCumulativeCycles;
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}
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size_t pos;
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const tape_data_t val = getCurrentWave(pos);
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const BYTE highBit = getBitValue(val);
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return highBit;
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}
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void CassetteTape::getTapeInfo(TapeInfo & info) const
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{
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info.filename = myFilename;
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const tape_data_t val = getCurrentWave(info.pos);
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info.bit = myLastBit;
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info.size = myData.size();
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info.frequency = myFrequency;
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}
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BYTE __stdcall TapeRead(WORD pc, WORD address, BYTE, BYTE, ULONG nExecutedCycles) // $C060 TAPEIN
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{
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if (g_Apple2Type == A2TYPE_PRAVETS8A)
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return GetPravets().GetKeycode( MemReadFloatingBus(nExecutedCycles) );
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const BYTE highBit = CassetteTape::instance().getValue(nExecutedCycles);
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return MemReadFloatingBus(highBit, nExecutedCycles);
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}
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BYTE __stdcall TapeWrite(WORD, WORD address, BYTE, BYTE, ULONG nExecutedCycles) // $C020 TAPEOUT
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{
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return 0;
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}
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