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Merge pull request #92 from TomHarte/MFMCleanup

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Adds some documentation and tidies some of the new MFM infrastructure
This commit is contained in:
Thomas Harte 2016-12-31 15:32:11 -05:00 committed by GitHub
commit 0689df1349
4 changed files with 63 additions and 45 deletions
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20
Components/1770/1770.cpp
View File

@ -175,22 +175,22 @@ void WD1770::process_input_bit(int value, unsigned int cycles_since_index_hole)
case Storage::Encodings::MFM::FMIndexAddressMark:
token_type = Token::Index;
crc_generator_.reset();
crc_generator_.add(Storage::Encodings::MFM::MFMIndexAddressByte);
crc_generator_.add(Storage::Encodings::MFM::IndexAddressByte);
break;
case Storage::Encodings::MFM::FMIDAddressMark:
token_type = Token::ID;
crc_generator_.reset();
crc_generator_.add(Storage::Encodings::MFM::MFMIDAddressByte);
crc_generator_.add(Storage::Encodings::MFM::IDAddressByte);
break;
case Storage::Encodings::MFM::FMDataAddressMark:
token_type = Token::Data;
crc_generator_.reset();
crc_generator_.add(Storage::Encodings::MFM::MFMDataAddressByte);
crc_generator_.add(Storage::Encodings::MFM::DataAddressByte);
break;
case Storage::Encodings::MFM::FMDeletedDataAddressMark:
token_type = Token::DeletedData;
crc_generator_.reset();
crc_generator_.add(Storage::Encodings::MFM::MFMDeletedDataAddressByte);
crc_generator_.add(Storage::Encodings::MFM::DeletedDataAddressByte);
break;
default:
break;
@ -242,16 +242,16 @@ void WD1770::process_input_bit(int value, unsigned int cycles_since_index_hole)
is_awaiting_marker_value_ = false;
switch(latest_token_.byte_value)
{
case Storage::Encodings::MFM::MFMIndexAddressByte:
case Storage::Encodings::MFM::IndexAddressByte:
latest_token_.type = Token::Index;
break;
case Storage::Encodings::MFM::MFMIDAddressByte:
case Storage::Encodings::MFM::IDAddressByte:
latest_token_.type = Token::ID;
break;
case Storage::Encodings::MFM::MFMDataAddressByte:
case Storage::Encodings::MFM::DataAddressByte:
latest_token_.type = Token::Data;
break;
case Storage::Encodings::MFM::MFMDeletedDataAddressByte:
case Storage::Encodings::MFM::DeletedDataAddressByte:
latest_token_.type = Token::DeletedData;
break;
default: break;
@ -662,12 +662,12 @@ void WD1770::posit_event(Event new_event_type)
{
crc_generator_.set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
write_byte((command_&0x01) ? Storage::Encodings::MFM::MFMDeletedDataAddressByte : Storage::Encodings::MFM::MFMDataAddressByte);
write_byte((command_&0x01) ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
}
else
{
crc_generator_.reset();
crc_generator_.add((command_&0x01) ? Storage::Encodings::MFM::MFMDeletedDataAddressByte : Storage::Encodings::MFM::MFMDataAddressByte);
crc_generator_.add((command_&0x01) ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
write_raw_short((command_&0x01) ? Storage::Encodings::MFM::FMDeletedDataAddressMark : Storage::Encodings::MFM::FMDataAddressMark);
}

19
Storage/Disk/Disk.hpp
View File

@ -115,13 +115,30 @@ class Disk {
*/
virtual std::shared_ptr<Track> get_uncached_track_at_position(unsigned int head, unsigned int position) = 0;
/*!
Subclasses that support writing should implement @c store_updated_track_at_position to determine which bytes
have to be written from @c track, then obtain @c file_access_mutex and write new data to their file to represent
the track underneath @c head at @c position.
The base class will ensure that calls are made to @c get_uncached_track_at_position only while it holds @c file_access_mutex;
that mutex therefore provides serialisation of file access.
This method will be called asynchronously. Subclasses are responsible for any synchronisation other than that
provided automatically via @c file_access_mutex.
*/
virtual void store_updated_track_at_position(unsigned int head, unsigned int position, const std::shared_ptr<Track> &track, std::mutex &file_access_mutex);
/*!
Subclasses that support writing should call @c flush_updates during their destructor if there is anything they
do in @c store_updated_track_at_position that would not be valid after their destructor has completed but prior
to Disk's constructor running.
*/
void flush_updates();
private:
std::map<int, std::shared_ptr<Track>> cached_tracks_;
int get_id_for_track_at_position(unsigned int head, unsigned int position);
std::map<int, std::shared_ptr<Track>> cached_tracks_;
std::mutex file_access_mutex_;
std::unique_ptr<Concurrency::AsyncTaskQueue> update_queue_;
};

54
Storage/Disk/Encodings/MFM.cpp
View File

@ -37,22 +37,22 @@ class MFMEncoder: public Encoder {
void add_index_address_mark() {
for(int c = 0; c < 3; c++) output_short(MFMIndexSync);
add_byte(MFMIndexAddressByte);
add_byte(IndexAddressByte);
}
void add_ID_address_mark() {
output_sync();
add_byte(MFMIDAddressByte);
add_byte(IDAddressByte);
}
void add_data_address_mark() {
output_sync();
add_byte(MFMDataAddressByte);
add_byte(DataAddressByte);
}
void add_deleted_data_address_mark() {
output_sync();
add_byte(MFMDeletedDataAddressByte);
add_byte(DeletedDataAddressByte);
}
private:
@ -92,28 +92,28 @@ class FMEncoder: public Encoder {
void add_index_address_mark()
{
crc_generator_.reset();
crc_generator_.add(MFMIndexAddressByte);
crc_generator_.add(IndexAddressByte);
output_short(FMIndexAddressMark);
}
void add_ID_address_mark()
{
crc_generator_.reset();
crc_generator_.add(MFMIDAddressByte);
crc_generator_.add(IDAddressByte);
output_short(FMIDAddressMark);
}
void add_data_address_mark()
{
crc_generator_.reset();
crc_generator_.add(MFMDataAddressByte);
crc_generator_.add(DataAddressByte);
output_short(FMDataAddressMark);
}
void add_deleted_data_address_mark()
{
crc_generator_.reset();
crc_generator_.add(MFMDeletedDataAddressByte);
crc_generator_.add(DeletedDataAddressByte);
output_short(FMDeletedDataAddressMark);
}
};
@ -282,7 +282,7 @@ void Parser::seek_to_track(uint8_t track)
}
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t track, uint8_t sector)
std::shared_ptr<Sector> Parser::get_sector(uint8_t track, uint8_t sector)
{
seek_to_track(track);
return get_sector(sector);
@ -408,9 +408,9 @@ std::vector<uint8_t> Parser::get_track()
{
switch(byte_value)
{
case MFMIDAddressByte: found_id = true; break;
case MFMDataAddressByte:
case MFMDeletedDataAddressByte: found_data = true; break;
case IDAddressByte: found_id = true; break;
case DataAddressByte:
case DeletedDataAddressByte: found_data = true; break;
}
}
}
@ -431,9 +431,9 @@ std::vector<uint8_t> Parser::get_track()
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
std::shared_ptr<Sector> Parser::get_next_sector()
{
std::shared_ptr<Storage::Encodings::MFM::Sector> sector(new Storage::Encodings::MFM::Sector);
std::shared_ptr<Sector> sector(new Sector);
index_count_ = 0;
while(index_count_ < 2)
@ -445,10 +445,10 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
run_for_cycles(1);
if(is_mfm_)
{
while(shift_register_ == Storage::Encodings::MFM::MFMSync)
while(shift_register_ == MFMSync)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMIDAddressByte)
if(mark == IDAddressByte)
{
crc_generator_.set_value(MFMPostSyncCRCValue);
id_found = true;
@ -458,7 +458,7 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark)
if(shift_register_ == FMIDAddressMark)
{
crc_generator_.reset();
id_found = true;
@ -467,7 +467,7 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
if(index_count_ >= 2) return nullptr;
}
crc_generator_.add(MFMIDAddressByte);
crc_generator_.add(IDAddressByte);
sector->track = get_next_byte();
sector->side = get_next_byte();
sector->sector = get_next_byte();
@ -483,30 +483,30 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
run_for_cycles(1);
if(is_mfm_)
{
while(shift_register_ == Storage::Encodings::MFM::MFMSync)
while(shift_register_ == MFMSync)
{
uint8_t mark = get_next_byte();
if(mark == Storage::Encodings::MFM::MFMDataAddressByte)
if(mark == DataAddressByte)
{
crc_generator_.set_value(MFMPostSyncCRCValue);
data_found = true;
break;
}
if(mark == Storage::Encodings::MFM::MFMIDAddressByte) return nullptr;
if(mark == IDAddressByte) return nullptr;
}
}
else
{
if(shift_register_ == Storage::Encodings::MFM::FMDataAddressMark)
if(shift_register_ == FMDataAddressMark)
{
crc_generator_.reset();
data_found = true;
}
if(shift_register_ == Storage::Encodings::MFM::FMIDAddressMark) return nullptr;
if(shift_register_ == FMIDAddressMark) return nullptr;
}
if(index_count_ >= 2) return nullptr;
}
crc_generator_.add(MFMDataAddressByte);
crc_generator_.add(DataAddressByte);
size_t data_size = (size_t)(128 << size);
sector->data.reserve(data_size);
@ -524,9 +524,9 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_next_sector()
return nullptr;
}
std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t sector)
std::shared_ptr<Sector> Parser::get_sector(uint8_t sector)
{
std::shared_ptr<Storage::Encodings::MFM::Sector> first_sector;
std::shared_ptr<Sector> first_sector;
index_count_ = 0;
while(!first_sector && index_count_ < 2) first_sector = get_next_sector();
if(!first_sector) return first_sector;
@ -534,7 +534,7 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t sect
while(1)
{
std::shared_ptr<Storage::Encodings::MFM::Sector> next_sector = get_next_sector();
std::shared_ptr<Sector> next_sector = get_next_sector();
if(!next_sector) continue;
if(next_sector->sector == first_sector->sector) return nullptr;
if(next_sector->sector == sector) return next_sector;

15
Storage/Disk/Encodings/MFM.hpp
View File

@ -19,18 +19,19 @@ namespace Storage {
namespace Encodings {
namespace MFM {
const uint8_t IndexAddressByte = 0xfc;
const uint8_t IDAddressByte = 0xfe;
const uint8_t DataAddressByte = 0xfb;
const uint8_t DeletedDataAddressByte = 0xf8;
const uint16_t FMIndexAddressMark = 0xf77a; // data 0xfc, with clock 0xd7 => 1111 1100 with clock 1101 0111 => 1111 0111 0111 1010
const uint16_t FMIDAddressMark = 0xf57e; // data 0xfe, with clock 0xc7 => 1111 1110 with clock 1100 0111 => 1111 0101 0111 1110
const uint16_t FMDataAddressMark = 0xf56f; // data 0xfb, with clock 0xc7 => 1111 1011 with clock 1100 0111 => 1111 0101 0110 1111
const uint16_t FMDeletedDataAddressMark = 0xf56a; // data 0xf8, with clock 0xc7 => 1111 1000 with clock 1100 0111 => 1111 0101 0110 1010
const uint16_t MFMIndexSync = 0x5224;
const uint16_t MFMSync = 0x4489;
const uint8_t MFMIndexAddressByte = 0xfc;
const uint8_t MFMIDAddressByte = 0xfe;
const uint8_t MFMDataAddressByte = 0xfb;
const uint8_t MFMDeletedDataAddressByte = 0xf8;
const uint16_t MFMPostSyncCRCValue = 0xcdb4;
const uint16_t MFMIndexSync = 0x5224; // data 0xc2, with a missing clock at 0x0080 => 0101 0010 1010 0100 without 1000 0000
const uint16_t MFMSync = 0x4489; // data 0xa1, with a missing clock at 0x0020 => 0100 0100 1010 1001 without 0010 0000
const uint16_t MFMPostSyncCRCValue = 0xcdb4; // the value the CRC generator should have after encountering three 0xa1s
struct Sector {
uint8_t track, side, sector;