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Factored out the standard [M]FM gap and mark groups, to increase 8272 readability and because it's pretty-much certain I'll need them again if ever I try to tackle e.g. the 8271.

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This commit is contained in:
Thomas Harte 2017-08-14 16:03:35 -04:00
parent 4df9307d25
commit a366298022
3 changed files with 82 additions and 56 deletions
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61
Components/8272/i8272.cpp
View File

@ -427,31 +427,11 @@ void i8272::posit_event(int event_type) {
write_data_found_header:
begin_writing();
if(get_is_double_density()) {
write_n_bytes(50, 0x4e);
write_n_bytes(12, 0x00);
} else {
write_n_bytes(11, 0xff);
write_n_bytes(6, 0x00);
}
WAIT_FOR_EVENT(Event::DataWritten);
{
bool is_deleted = (command_[0] & 0x1f) == 0x09;
if(get_is_double_density()) {
get_crc_generator().set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
write_byte(is_deleted ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
} else {
get_crc_generator().reset();
get_crc_generator().add(is_deleted ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
write_raw_short(is_deleted ? Storage::Encodings::MFM::FMDeletedDataAddressMark : Storage::Encodings::MFM::FMDataAddressMark);
}
}
write_id_data_joiner((command_[0] & 0x1f) == 0x09);
SetDataDirectionFromProcessor();
SetDataRequest();
WAIT_FOR_EVENT(Event::DataWritten);
expects_input_ = true;
distance_into_section_ = 0;
@ -563,32 +543,12 @@ void i8272::posit_event(int event_type) {
begin_writing();
// Write start-of-track.
if(get_is_double_density()) {
write_n_bytes(80, 0x4e);
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMIndexSync);
write_byte(Storage::Encodings::MFM::IndexAddressByte);
write_n_bytes(50, 0x4e);
} else {
write_n_bytes(40, 0xff);
write_n_bytes(6, 0x00);
write_raw_short(Storage::Encodings::MFM::FMIndexAddressMark);
write_n_bytes(26, 0xff);
}
write_start_of_track();
WAIT_FOR_EVENT(Event::DataWritten);
sector_ = 0;
format_track_write_sector:
if(get_is_double_density()) {
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
get_crc_generator().set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
write_byte(Storage::Encodings::MFM::IDAddressByte);
} else {
write_n_bytes(6, 0x00);
get_crc_generator().reset();
write_raw_short(Storage::Encodings::MFM::FMIDAddressMark);
}
write_id_joiner();
// Write the sector header, obtaining its contents
// from the processor.
@ -610,18 +570,7 @@ void i8272::posit_event(int event_type) {
write_crc();
// Write the sector body.
if(get_is_double_density()) {
write_n_bytes(22, 0x4e);
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
get_crc_generator().set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
write_byte(Storage::Encodings::MFM::DataAddressByte);
} else {
write_n_bytes(11, 0xff);
write_n_bytes(6, 0x00);
get_crc_generator().reset();
write_raw_short(Storage::Encodings::MFM::FMDataAddressMark);
}
write_id_data_joiner(false);
write_n_bytes(128 << command_[2], command_[5]);
write_crc();

52
Storage/Disk/MFMDiskController.cpp
View File

@ -185,3 +185,55 @@ void MFMController::write_crc() {
void MFMController::write_n_bytes(int quantity, uint8_t value) {
while(quantity--) write_byte(value);
}
void MFMController::write_id_joiner() {
if(get_is_double_density()) {
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
get_crc_generator().set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
write_byte(Storage::Encodings::MFM::IDAddressByte);
} else {
write_n_bytes(6, 0x00);
get_crc_generator().reset();
write_raw_short(Storage::Encodings::MFM::FMIDAddressMark);
}
}
void MFMController::write_id_data_joiner(bool is_deleted) {
if(get_is_double_density()) {
write_n_bytes(22, 0x4e);
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMSync);
get_crc_generator().set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
write_byte(is_deleted ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
} else {
write_n_bytes(11, 0xff);
write_n_bytes(6, 0x00);
get_crc_generator().reset();
get_crc_generator().add(is_deleted ? Storage::Encodings::MFM::DeletedDataAddressByte : Storage::Encodings::MFM::DataAddressByte);
write_raw_short(is_deleted ? Storage::Encodings::MFM::FMDeletedDataAddressMark : Storage::Encodings::MFM::FMDataAddressMark);
}
}
void MFMController::write_post_data_gap() {
if(get_is_double_density()) {
write_n_bytes(54, 0x4e);
} else {
write_n_bytes(27, 0xff);
}
}
void MFMController::write_start_of_track() {
if(get_is_double_density()) {
write_n_bytes(80, 0x4e);
write_n_bytes(12, 0x00);
for(int c = 0; c < 3; c++) write_raw_short(Storage::Encodings::MFM::MFMIndexSync);
write_byte(Storage::Encodings::MFM::IndexAddressByte);
write_n_bytes(50, 0x4e);
} else {
write_n_bytes(40, 0xff);
write_n_bytes(6, 0x00);
write_raw_short(Storage::Encodings::MFM::FMIndexAddressMark);
write_n_bytes(26, 0xff);
}
}

25
Storage/Disk/MFMDiskController.hpp
View File

@ -118,6 +118,31 @@ class MFMController: public Controller {
*/
void write_n_bytes(int quantity, uint8_t value);
/*!
Writes everything that should, per the spec, appear prior to the address contained
in an ID mark — proper gaps and the ID mark — and appropriate seeds the CRC generator.
*/
void write_id_joiner();
/*!
Writes everything that should, per the spec, appear after the ID's CRC, up to and
including the mark that indicates the beginning of data, appropriately seeding
the CRC generator.
*/
void write_id_data_joiner(bool is_deleted);
/*!
Writes the gap expected after a sector's data CRC and before the beginning of the
next ID joiner.
*/
void write_post_data_gap();
/*!
Writes everything that should, per the spec, following the index hole and prior
to any sectors.
*/
void write_start_of_track();
private:
// Storage::Disk::Controller
virtual void process_input_bit(int value, unsigned int cycles_since_index_hole);