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Adds support for STX speed zones.

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This commit is contained in:
Thomas Harte 2020-01-19 12:38:33 -05:00
parent 50348c9fe7
commit f34ddce28f
1 changed files with 44 additions and 17 deletions
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61
Storage/Disk/DiskImage/Formats/STX.cpp
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@ -201,7 +201,7 @@ class TrackConstructor {
// Otherwise, seek to encode the sectors, using the track data to
// fill in the gaps (if provided).
std::unique_ptr<Storage::Encodings::MFM::Encoder> encoder;
std::unique_ptr<PCMSegment> segment;
std::vector<PCMSegment> segments;
// To reconcile the list of sectors with the WD get track-style track image,
// use sector bodies as definitive and refer to the track image for in-fill.
@ -256,11 +256,18 @@ class TrackConstructor {
}
}
// Just create an encoder if one doesn't exist. TODO: factor in data rate.
if(!encoder) {
segment.reset(new PCMSegment);
encoder = Storage::Encodings::MFM::GetMFMEncoder(segment->data);
}
const auto encoder_at_rate = [&encoder, &segments](unsigned int rate) -> Storage::Encodings::MFM::Encoder* {
if(!encoder) {
segments.emplace_back();
segments.back().length_of_a_bit = Storage::Time(int(rate), 1);
encoder = Storage::Encodings::MFM::GetMFMEncoder(segments.back().data);
} else if(segments.back().length_of_a_bit.length != rate) {
segments.emplace_back();
segments.back().length_of_a_bit = Storage::Time(int(rate), 1);
encoder->reset_target(segments.back().data);
}
return encoder.get();
};
// Write out, being wary of potential overlapping sectors, and copying from track_data_ to fill in gaps.
auto location = locations.begin();
@ -269,8 +276,9 @@ class TrackConstructor {
// assert(location->position >= track_position && location->position < track_data_.end());
// Advance to location.position.
auto default_rate_encoder = encoder_at_rate(128);
while(track_position < location->position) {
encoder->add_byte(*track_position);
default_rate_encoder->add_byte(*track_position);
++track_position;
}
@ -279,14 +287,14 @@ class TrackConstructor {
switch(location->type) {
default:
case Location::Address:
encoder->add_ID_address_mark();
default_rate_encoder->add_ID_address_mark();
bytes_to_write = 6;
break;
case Location::Data:
if(location->sector.status & 0x20)
encoder->add_deleted_data_address_mark();
default_rate_encoder->add_deleted_data_address_mark();
else
encoder->add_data_address_mark();
default_rate_encoder->add_data_address_mark();
bytes_to_write = location->sector.data_size() + 2;
break;
}
@ -306,16 +314,27 @@ class TrackConstructor {
default:
case Location::Address:
for(size_t c = 0; c < bytes_to_write; ++c)
encoder->add_byte(location->sector.address[c]);
default_rate_encoder->add_byte(location->sector.address[c]);
break;
case Location::Data: {
const auto body_bytes = std::min(bytes_to_write, size_t(location->sector.data_size()));
for(size_t c = 0; c < body_bytes; ++c)
encoder->add_byte(location->sector.contents[c]);
// If timing information is attached to this sector, write each byte at the proper speed.
// (TODO: is there any benefit to optiming number of calls to encoder_at_rate?)
if(!location->sector.timing.empty()) {
for(size_t c = 0; c < body_bytes; ++c) {
encoder_at_rate(location->sector.timing[c >> 4])->add_byte(location->sector.contents[c]);
}
} else {
for(size_t c = 0; c < body_bytes; ++c) {
default_rate_encoder->add_byte(location->sector.contents[c]);
}
}
// Add a CRC only if it fits (TODO: crop if necessary?).
if(bytes_to_write & 127) {
encoder->add_crc((location->sector.status & 0x18) == 0x10);
default_rate_encoder = encoder_at_rate(128);
default_rate_encoder->add_crc((location->sector.status & 0x18) == 0x10);
}
} break;
}
@ -330,20 +349,28 @@ class TrackConstructor {
++track_position;
}
// Count total size of track.
size_t track_size = 0;
for(auto &segment: segments) {
track_size += segment.data.size();
}
// Write generic padding up until the specified track size.
while(segment->data.size() < track_size_ * 16) {
while(track_size < track_size_ * 16) {
encoder->add_byte(0x4e);
track_size += 16;
}
// Pad out to the minimum size a WD can actually make sense of.
// I've no idea why it's valid for tracks to be shorter than this,
// so likely I'm suffering a comprehansion deficiency.
// TODO: determine why this isn't correct (or, possibly, is).
while(segment->data.size() < 5750 * 16) {
while(track_size < 5750 * 16) {
encoder->add_byte(0x4e);
track_size += 16;
}
return std::make_shared<PCMTrack>(*segment);
return std::make_shared<PCMTrack>(segments);
}
private: