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Factored the MFM parser out into encodings.

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This commit is contained in:
Thomas Harte 2016-12-25 20:00:57 -05:00
parent 1349e85d83
commit beaa868079
4 changed files with 181 additions and 174 deletions
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2
Components/1770/1770.cpp
View File

@ -632,9 +632,7 @@ void WD1770::posit_event(Event new_event_type)
update_status([] (Status &status) {
status.data_request = true;
});
printf("- %d\n", counter);
WAIT_FOR_EVENT(Event::DataWritten);
printf("+ %d\n", counter);
distance_into_section_++;
if(distance_into_section_ == 128 << header_[3])
{

174
StaticAnalyser/Acorn/Disk.cpp
View File

@ -14,180 +14,11 @@
using namespace StaticAnalyser::Acorn;
class FMParser: public Storage::Disk::Controller {
public:
std::shared_ptr<Storage::Disk::Drive> drive;
FMParser(bool is_mfm) :
Storage::Disk::Controller(4000000, 1, 300),
crc_generator_(0x1021, 0xffff),
shift_register_(0), track_(0), is_mfm_(is_mfm)
{
Storage::Time bit_length;
bit_length.length = 1;
bit_length.clock_rate = is_mfm ? 500000 : 250000; // i.e. 250 kbps (including clocks)
set_expected_bit_length(bit_length);
drive.reset(new Storage::Disk::Drive);
set_drive(drive);
set_motor_on(true);
}
/*!
Attempts to read the sector located at @c track and @c sector.
@returns a sector if one was found; @c nullptr otherwise.
*/
std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t track, uint8_t sector)
{
int difference = (int)track - (int)track_;
track_ = track;
if(difference)
{
int direction = difference < 0 ? -1 : 1;
difference *= direction;
for(int c = 0; c < difference; c++) step(direction);
}
return get_sector(sector);
}
private:
unsigned int shift_register_;
int index_count_;
uint8_t track_;
int bit_count_;
std::shared_ptr<Storage::Encodings::MFM::Sector> sector_cache_[65536];
NumberTheory::CRC16 crc_generator_;
bool is_mfm_;
void process_input_bit(int value, unsigned int cycles_since_index_hole)
{
shift_register_ = ((shift_register_ << 1) | (unsigned int)value) & 0xffff;
bit_count_++;
}
void process_index_hole()
{
index_count_++;
}
uint8_t get_next_byte()
{
bit_count_ = 0;
while(bit_count_ < 16) run_for_cycles(1);
uint8_t byte = (uint8_t)(
((shift_register_&0x0001) >> 0) |
((shift_register_&0x0004) >> 1) |
((shift_register_&0x0010) >> 2) |
((shift_register_&0x0040) >> 3) |
((shift_register_&0x0100) >> 4) |
((shift_register_&0x0400) >> 5) |
((shift_register_&0x1000) >> 6) |
((shift_register_&0x4000) >> 7));
crc_generator_.add(byte);
return byte;
}
std::shared_ptr<Storage::Encodings::MFM::Sector> get_next_sector()
{
std::shared_ptr<Storage::Encodings::MFM::Sector> sector(new Storage::Encodings::MFM::Sector);
index_count_ = 0;
while(index_count_ < 2)
{
// look for an ID address mark
while(1)
{
run_for_cycles(1);
if(is_mfm_)
{
if(shift_register_ == Storage::Encodings::MFM::MFMAddressMark)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMIDAddressByte) break;
}
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark) break;
}
if(index_count_ >= 2) return nullptr;
}
crc_generator_.reset();
sector->track = get_next_byte();
sector->side = get_next_byte();
sector->sector = get_next_byte();
uint8_t size = get_next_byte();
uint16_t header_crc = crc_generator_.get_value();
if((header_crc >> 8) != get_next_byte()) continue;
if((header_crc & 0xff) != get_next_byte()) continue;
// look for data mark
while(1)
{
run_for_cycles(1);
if(is_mfm_)
{
if(shift_register_ == Storage::Encodings::MFM::MFMAddressMark)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMDataAddressByte) break;
if(mark == Storage::Encodings::MFM::MFMIDAddressByte) return nullptr;
}
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMDataAddressMark) break;
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark) return nullptr;
}
if(index_count_ >= 2) return nullptr;
}
size_t data_size = (size_t)(128 << size);
sector->data.reserve(data_size);
crc_generator_.reset();
for(size_t c = 0; c < data_size; c++)
{
sector->data.push_back(get_next_byte());
}
uint16_t data_crc = crc_generator_.get_value();
if((data_crc >> 8) != get_next_byte()) continue;
if((data_crc & 0xff) != get_next_byte()) continue;
return sector;
}
return nullptr;
}
std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t sector)
{
// uint16_t sector_address = (uint16_t)((track_ << 8) | sector);
// if(sector_cache_[sector_address]) return sector_cache_[sector_address];
std::shared_ptr<Storage::Encodings::MFM::Sector> first_sector = get_next_sector();
if(!first_sector) return first_sector;
if(first_sector->sector == sector) return first_sector;
while(1)
{
std::shared_ptr<Storage::Encodings::MFM::Sector> next_sector = get_next_sector();
if(next_sector->sector == first_sector->sector) return nullptr;
if(next_sector->sector == sector) return next_sector;
}
}
};
std::unique_ptr<Catalogue> StaticAnalyser::Acorn::GetDFSCatalogue(const std::shared_ptr<Storage::Disk::Disk> &disk)
{
// c.f. http://beebwiki.mdfs.net/Acorn_DFS_disc_format
std::unique_ptr<Catalogue> catalogue(new Catalogue);
FMParser parser(false);
parser.drive->set_disk(disk);
Storage::Encodings::MFM::Parser parser(false, disk);
std::shared_ptr<Storage::Encodings::MFM::Sector> names = parser.get_sector(0, 0);
std::shared_ptr<Storage::Encodings::MFM::Sector> details = parser.get_sector(0, 1);
@ -248,8 +79,7 @@ std::unique_ptr<Catalogue> StaticAnalyser::Acorn::GetDFSCatalogue(const std::sha
std::unique_ptr<Catalogue> StaticAnalyser::Acorn::GetADFSCatalogue(const std::shared_ptr<Storage::Disk::Disk> &disk)
{
std::unique_ptr<Catalogue> catalogue(new Catalogue);
FMParser parser(true);
parser.drive->set_disk(disk);
Storage::Encodings::MFM::Parser parser(true, disk);
std::shared_ptr<Storage::Encodings::MFM::Sector> free_space_map_second_half = parser.get_sector(0, 1);
if(!free_space_map_second_half) return nullptr;

149
Storage/Disk/Encodings/MFM.cpp
View File

@ -211,3 +211,152 @@ std::unique_ptr<Encoder> Storage::Encodings::MFM::GetFMEncoder(std::vector<uint8
{
return std::unique_ptr<Encoder>(new FMEncoder(target));
}
#pragma mark - Parser
Parser::Parser(bool is_mfm, const std::shared_ptr<Storage::Disk::Disk> &disk) :
Storage::Disk::Controller(4000000, 1, 300),
crc_generator_(0x1021, 0xffff),
shift_register_(0), track_(0), is_mfm_(is_mfm)
{
Storage::Time bit_length;
bit_length.length = 1;
bit_length.clock_rate = is_mfm ? 500000 : 250000; // i.e. 250 kbps (including clocks)
set_expected_bit_length(bit_length);
drive.reset(new Storage::Disk::Drive);
drive->set_disk(disk);
set_drive(drive);
set_motor_on(true);
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t track, uint8_t sector)
{
int difference = (int)track - (int)track_;
track_ = track;
if(difference)
{
int direction = difference < 0 ? -1 : 1;
difference *= direction;
for(int c = 0; c < difference; c++) step(direction);
}
return get_sector(sector);
}
void Parser::process_input_bit(int value, unsigned int cycles_since_index_hole)
{
shift_register_ = ((shift_register_ << 1) | (unsigned int)value) & 0xffff;
bit_count_++;
}
void Parser::process_index_hole()
{
index_count_++;
}
uint8_t Parser::get_next_byte()
{
bit_count_ = 0;
while(bit_count_ < 16) run_for_cycles(1);
uint8_t byte = (uint8_t)(
((shift_register_&0x0001) >> 0) |
((shift_register_&0x0004) >> 1) |
((shift_register_&0x0010) >> 2) |
((shift_register_&0x0040) >> 3) |
((shift_register_&0x0100) >> 4) |
((shift_register_&0x0400) >> 5) |
((shift_register_&0x1000) >> 6) |
((shift_register_&0x4000) >> 7));
crc_generator_.add(byte);
return byte;
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
{
std::shared_ptr<Storage::Encodings::MFM::Sector> sector(new Storage::Encodings::MFM::Sector);
index_count_ = 0;
while(index_count_ < 2)
{
// look for an ID address mark
while(1)
{
run_for_cycles(1);
if(is_mfm_)
{
if(shift_register_ == Storage::Encodings::MFM::MFMAddressMark)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMIDAddressByte) break;
}
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark) break;
}
if(index_count_ >= 2) return nullptr;
}
crc_generator_.reset();
sector->track = get_next_byte();
sector->side = get_next_byte();
sector->sector = get_next_byte();
uint8_t size = get_next_byte();
uint16_t header_crc = crc_generator_.get_value();
if((header_crc >> 8) != get_next_byte()) continue;
if((header_crc & 0xff) != get_next_byte()) continue;
// look for data mark
while(1)
{
run_for_cycles(1);
if(is_mfm_)
{
if(shift_register_ == Storage::Encodings::MFM::MFMAddressMark)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMDataAddressByte) break;
if(mark == Storage::Encodings::MFM::MFMIDAddressByte) return nullptr;
}
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMDataAddressMark) break;
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark) return nullptr;
}
if(index_count_ >= 2) return nullptr;
}
size_t data_size = (size_t)(128 << size);
sector->data.reserve(data_size);
crc_generator_.reset();
for(size_t c = 0; c < data_size; c++)
{
sector->data.push_back(get_next_byte());
}
uint16_t data_crc = crc_generator_.get_value();
if((data_crc >> 8) != get_next_byte()) continue;
if((data_crc & 0xff) != get_next_byte()) continue;
return sector;
}
return nullptr;
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t sector)
{
std::shared_ptr<Storage::Encodings::MFM::Sector> first_sector = get_next_sector();
if(!first_sector) return first_sector;
if(first_sector->sector == sector) return first_sector;
while(1)
{
std::shared_ptr<Storage::Encodings::MFM::Sector> next_sector = get_next_sector();
if(next_sector->sector == first_sector->sector) return nullptr;
if(next_sector->sector == sector) return next_sector;
}
}

30
Storage/Disk/Encodings/MFM.hpp
View File

@ -12,6 +12,8 @@
#include <cstdint>
#include <vector>
#include "../Disk.hpp"
#include "../DiskController.hpp"
#include "../../../NumberTheory/CRC.hpp"
namespace Storage {
namespace Encodings {
@ -56,6 +58,34 @@ class Encoder {
std::unique_ptr<Encoder> GetMFMEncoder(std::vector<uint8_t> &target);
std::unique_ptr<Encoder> GetFMEncoder(std::vector<uint8_t> &target);
class Parser: public Storage::Disk::Controller {
public:
Parser(bool is_mfm, const std::shared_ptr<Storage::Disk::Disk> &disk);
/*!
Attempts to read the sector located at @c track and @c sector.
@returns a sector if one was found; @c nullptr otherwise.
*/
std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t track, uint8_t sector);
private:
std::shared_ptr<Storage::Disk::Drive> drive;
unsigned int shift_register_;
int index_count_;
uint8_t track_;
int bit_count_;
NumberTheory::CRC16 crc_generator_;
bool is_mfm_;
void process_input_bit(int value, unsigned int cycles_since_index_hole);
void process_index_hole();
uint8_t get_next_byte();
std::shared_ptr<Storage::Encodings::MFM::Sector> get_next_sector();
std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t sector);
};
}
}
}