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Made an attempt at format a track.

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This commit is contained in:
Thomas Harte
2017-08-13 18:05:19 -04:00
parent 6e36f8ffa4
commit e1e9a06712
3 changed files with 107 additions and 7 deletions
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Components/8272/i8272.cpp
+99 -7
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@@ -476,11 +476,7 @@ void i8272::posit_event(int event_type) {
goto write_loop;
}
{
uint16_t crc = get_crc_generator().get_value();
write_byte(crc >> 8);
write_byte(crc & 0xff);
}
write_crc();
expects_input_ = false;
WAIT_FOR_EVENT(Event::DataWritten);
end_writing();
@@ -518,8 +514,104 @@ void i8272::posit_event(int event_type) {
goto post_st012chrn;
format_track:
printf("Fromat track unimplemented!!\n");
goto wait_for_command;
printf("Format track\n");
SET_DRIVE_HEAD_MFM();
LOAD_HEAD();
CLEAR_STATUS();
// Wait for the index hole.
WAIT_FOR_EVENT(Event::IndexHole);
begin_writing();
// Write start-of-track.
// TODO: single density.
for(int c = 0; c < 80; c++) {
write_byte(0x4e);
}
for(int c = 0; c < 12; c++) {
write_byte(0x00);
}
for(int c = 0; c < 3; c++) {
write_raw_short(Storage::Encodings::MFM::MFMIndexSync);
}
write_byte(Storage::Encodings::MFM::IndexAddressByte);
for(int c = 0; c < 50; c++) {
write_byte(0x4e);
}
WAIT_FOR_EVENT(Event::DataWritten);
sector_ = 0;
format_track_write_sector:
for(int c = 0; c < 12; c++) {
write_byte(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);
// Write the sector header, obtaining its contents
// from the processor.
SetDataDirectionFromProcessor();
SetDataRequest();
expects_input_ = true;
distance_into_section_ = 0;
format_track_write_header:
WAIT_FOR_EVENT(Event::DataWritten);
// TODO: overrun?
header_[distance_into_section_] = input_;
write_byte(input_);
has_input_ = false;
distance_into_section_++;
if(distance_into_section_ < 4) {
SetDataRequest();
goto format_track_write_header;
}
write_crc();
// Write the sector body.
for(int c = 0; c < 22; c++) {
write_byte(0x4e);
}
for(int c = 0; c < 12; c++) {
write_byte(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);
for(int c = 0; c < (128 << command_[2]); c++) {
write_byte(command_[5]);
}
write_crc();
// Write the prescribed gap.
for(int c = 0; c < command_[4]; c++) {
write_byte(0x4e);
}
// Consider repeating.
sector_++;
if(sector_ < command_[3]) {
goto format_track_write_sector;
}
// Otherwise, pad out to the index hole.
format_track_pad:
write_byte(0x4e);
WAIT_FOR_EVENT((int)Event::DataWritten | (int)Event::IndexHole);
if(event_type != (int)Event::IndexHole) goto format_track_pad;
end_writing();
cylinder_ = header_[0];
head_ = header_[1];
sector_ = header_[2] + 1;
size_ = header_[3];
goto post_st012chrn;
scan_low:
printf("Scan low unimplemented!!\n");