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This has now successfully loaded its first PRG-as-a-tape.

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This commit is contained in:
Thomas Harte 2016-08-19 10:58:42 -04:00
parent 902c0f967a
commit 4edd1214f1
3 changed files with 60 additions and 50 deletions
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14
Machines/Commodore/Vic-20/Vic20.cpp
View File

@ -108,10 +108,10 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
// printf("%04x\n", address); // printf("%04x\n", address);
// } // }
if(operation == CPU6502::BusOperation::Write && (address >= 0x033C && address < 0x033C + 192)) // if(operation == CPU6502::BusOperation::Write && (address >= 0x033C && address < 0x033C + 192))
{ // {
printf("\n[%04x] <- %02x\n", address, *value); // printf("\n[%04x] <- %02x\n", address, *value);
} // }
// run the phase-1 part of this cycle, in which the VIC accesses memory // run the phase-1 part of this cycle, in which the VIC accesses memory
_mos6560->run_for_cycles(1); _mos6560->run_for_cycles(1);
@ -238,11 +238,11 @@ void Machine::set_prg(const char *file_name, size_t length, const uint8_t *data)
_rom_length = (uint16_t)(length - 2); _rom_length = (uint16_t)(length - 2);
// install in the ROM area if this looks like a ROM; otherwise put on tape and throw into that mechanism // install in the ROM area if this looks like a ROM; otherwise put on tape and throw into that mechanism
if(_rom_address == 0xa000 && (_rom_length == 0x1000 || _rom_length == 0x2000)) if(_rom_address == 0xa000)
{ {
_rom = new uint8_t[length - 2]; _rom = new uint8_t[0x2000];
memcpy(_rom, &data[2], length - 2); memcpy(_rom, &data[2], length - 2);
write_to_map(_processorReadMemoryMap, _rom, _rom_address, _rom_length); write_to_map(_processorReadMemoryMap, _rom, _rom_address, 0x2000);
} }
else else
{ {

93
Storage/Tape/Formats/TapePRG.cpp
View File

@ -29,9 +29,6 @@ TapePRG::TapePRG(const char *file_name) : _file(nullptr), _bitPhase(3), _filePha
_load_address |= (uint16_t)fgetc(_file) << 8; _load_address |= (uint16_t)fgetc(_file) << 8;
_length = (uint16_t)(file_stats.st_size - 2); _length = (uint16_t)(file_stats.st_size - 2);
fseek(_file, 2, SEEK_SET);
if (_load_address + _length >= 65536) if (_load_address + _length >= 65536)
throw ErrorBadFormat; throw ErrorBadFormat;
} }
@ -53,6 +50,8 @@ Tape::Pulse TapePRG::get_next_pulse()
if(!_bitPhase) get_next_output_token(); if(!_bitPhase) get_next_output_token();
Tape::Pulse pulse; Tape::Pulse pulse;
pulse.length.clock_rate = 1000000;
pulse.type = (_bitPhase&1) ? Pulse::High : Pulse::Low;
switch(_outputToken) switch(_outputToken)
{ {
case Leader: pulse.length.length = leader_zero_length; break; case Leader: pulse.length.length = leader_zero_length; break;
@ -60,9 +59,8 @@ Tape::Pulse TapePRG::get_next_pulse()
case One: pulse.length.length = (_bitPhase&2) ? zero_length : one_length; break; case One: pulse.length.length = (_bitPhase&2) ? zero_length : one_length; break;
case WordMarker: pulse.length.length = (_bitPhase&2) ? one_length : marker_length; break; case WordMarker: pulse.length.length = (_bitPhase&2) ? one_length : marker_length; break;
case EndOfBlock: pulse.length.length = (_bitPhase&2) ? zero_length : marker_length; break; case EndOfBlock: pulse.length.length = (_bitPhase&2) ? zero_length : marker_length; break;
case Silence: pulse.type = Pulse::Zero; pulse.length.length = 5000; break;
} }
pulse.length.clock_rate = 1000000;
pulse.type = (_bitPhase&1) ? Pulse::High : Pulse::Low;
return pulse; return pulse;
} }
@ -79,17 +77,23 @@ void TapePRG::get_next_output_token()
{ {
static const int block_length = 192; // not counting the checksum static const int block_length = 192; // not counting the checksum
static const int countdown_bytes = 9; static const int countdown_bytes = 9;
static const int leadin_length = 20000;
static const int block_leadin_length = 5000;
if(_filePhase == FilePhaseHeaderDataGap)
{
_outputToken = Silence;
_filePhase = FilePhaseData;
return;
}
// the lead-in is 20,000 instances of the lead-in pair; every other phase begins with 5000 // the lead-in is 20,000 instances of the lead-in pair; every other phase begins with 5000
// before doing whatever it should be doing // before doing whatever it should be doing
if((_filePhase == FilePhaseLeadIn || _filePhase == FilePhaseHeaderDataGap) || _phaseOffset < 50) if(_filePhase == FilePhaseLeadIn || _phaseOffset < block_leadin_length)
{ {
_outputToken = Leader; _outputToken = Leader;
_phaseOffset++; _phaseOffset++;
if( if(_filePhase == FilePhaseLeadIn && _phaseOffset == leadin_length)
(_filePhase == FilePhaseLeadIn && _phaseOffset == 20000) ||
(_filePhase == FilePhaseHeaderDataGap && _phaseOffset == 5586)
)
{ {
_phaseOffset = 0; _phaseOffset = 0;
_filePhase = (_filePhase == FilePhaseLeadIn) ? FilePhaseHeader : FilePhaseData; _filePhase = (_filePhase == FilePhaseLeadIn) ? FilePhaseHeader : FilePhaseData;
@ -98,12 +102,17 @@ void TapePRG::get_next_output_token()
} }
// determine whether a new byte needs to be queued up // determine whether a new byte needs to be queued up
int block_offset = _phaseOffset - 50; int block_offset = _phaseOffset - block_leadin_length;
int bit_offset = block_offset % 10; int bit_offset = block_offset % 10;
int byte_offset = block_offset / 10; int byte_offset = block_offset / 10;
_phaseOffset++; _phaseOffset++;
if(byte_offset == block_length + countdown_bytes + 1) // i.e. after the checksum if(!bit_offset &&
(
(_filePhase == FilePhaseHeader && byte_offset == block_length + countdown_bytes + 1) ||
feof(_file)
)
)
{ {
_outputToken = EndOfBlock; _outputToken = EndOfBlock;
_phaseOffset = 0; _phaseOffset = 0;
@ -111,22 +120,16 @@ void TapePRG::get_next_output_token()
switch(_filePhase) switch(_filePhase)
{ {
default: break; default: break;
// case FilePhaseLeadIn:
// _filePhase = FilePhaseHeader;
// break;
case FilePhaseHeader: case FilePhaseHeader:
_copy_mask ^= 0x80; _copy_mask ^= 0x80;
if(_copy_mask) _filePhase = FilePhaseHeaderDataGap; if(_copy_mask) _filePhase = FilePhaseHeaderDataGap;
break; break;
case FilePhaseData: case FilePhaseData:
if(feof(_file)) _copy_mask ^= 0x80;
{ fseek(_file, 2, SEEK_SET);
_copy_mask ^= 0x80; if(_copy_mask) reset();
fseek(_file, 2, SEEK_SET);
}
break; break;
} }
printf("\n===\n");
return; return;
} }
@ -137,41 +140,48 @@ void TapePRG::get_next_output_token()
{ {
_output_byte = (uint8_t)(countdown_bytes - byte_offset) | _copy_mask; _output_byte = (uint8_t)(countdown_bytes - byte_offset) | _copy_mask;
} }
else if(byte_offset == countdown_bytes + block_length)
{
_output_byte = _check_digit;
}
else else
{ {
if(byte_offset == countdown_bytes) _check_digit = 0;
if(_filePhase == FilePhaseHeader) if(_filePhase == FilePhaseHeader)
{ {
switch(byte_offset - countdown_bytes) if(byte_offset == countdown_bytes + block_length)
{ {
case 0: _output_byte = 0x03; break; _output_byte = _check_digit;
case 1: _output_byte = _load_address & 0xff; break; }
case 2: _output_byte = (_load_address >> 8)&0xff; break; else
case 3: _output_byte = (_load_address + _length) & 0xff; break; {
case 4: _output_byte = ((_load_address + _length) >> 8) & 0xff; break; if(byte_offset == countdown_bytes) _check_digit = 0;
if(_filePhase == FilePhaseHeader)
{
switch(byte_offset - countdown_bytes)
{
case 0: _output_byte = 0x03; break;
case 1: _output_byte = _load_address & 0xff; break;
case 2: _output_byte = (_load_address >> 8)&0xff; break;
case 3: _output_byte = (_load_address + _length) & 0xff; break;
case 4: _output_byte = ((_load_address + _length) >> 8) & 0xff; break;
case 5: _output_byte = 0x50; break; // P case 5: _output_byte = 0x50; break; // P
case 6: _output_byte = 0x52; break; // R case 6: _output_byte = 0x52; break; // R
case 7: _output_byte = 0x47; break; // G case 7: _output_byte = 0x47; break; // G
default: default:
_output_byte = 0x20; _output_byte = 0x20;
break; break;
}
}
} }
} }
else else
{ {
_output_byte = (uint8_t)fgetc(_file); _output_byte = (uint8_t)fgetc(_file);
if(feof(_file)) _output_byte = 0x00; if(feof(_file))
{
_output_byte = _check_digit;
}
} }
_check_digit ^= _output_byte; _check_digit ^= _output_byte;
} }
printf(" %02x", _output_byte);
} }
switch(bit_offset) switch(bit_offset)
@ -189,7 +199,6 @@ void TapePRG::get_next_output_token()
parity ^= (parity >> 2); parity ^= (parity >> 2);
parity ^= (parity >> 1); parity ^= (parity >> 1);
_outputToken = (parity&1) ? Zero : One; _outputToken = (parity&1) ? Zero : One;
printf("[%d]", parity&1);
} }
break; break;
} }

3
Storage/Tape/Formats/TapePRG.hpp
View File

@ -55,7 +55,8 @@ class TapePRG: public Tape {
Zero, Zero,
One, One,
WordMarker, WordMarker,
EndOfBlock EndOfBlock,
Silence
} _outputToken; } _outputToken;
void get_next_output_token(); void get_next_output_token();
uint8_t _output_byte; uint8_t _output_byte;