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CLK/Analyser/Static/Commodore/Disk.cpp

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//
// Disk.cpp
// Clock Signal
//
// Created by Thomas Harte on 13/09/2016.
// Copyright 2016 Thomas Harte. All rights reserved.
//
#include "Disk.hpp"
#include "../../../Storage/Disk/Controller/DiskController.hpp"
#include "../../../Storage/Disk/Encodings/CommodoreGCR.hpp"
#include "../../../Storage/Data/Commodore.hpp"
#include <limits>
#include <vector>
#include <array>
using namespace Analyser::Static::Commodore;
class CommodoreGCRParser: public Storage::Disk::Controller {
public:
CommodoreGCRParser() : Storage::Disk::Controller(4000000), shift_register_(0), track_(1) {
emplace_drive(4000000, 300, 2);
set_drive(1);
get_drive().set_motor_on(true);
}
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struct Sector {
uint8_t sector, track;
std::array<uint8_t, 256> data;
bool header_checksum_matched;
bool data_checksum_matched;
};
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/*!
Attempts to read the sector located at @c track and @c sector.
@returns a sector if one was found; @c nullptr otherwise.
*/
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std::shared_ptr<Sector> get_sector(uint8_t track, uint8_t sector) {
int difference = int(track) - int(track_);
track_ = track;
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if(difference) {
int direction = difference < 0 ? -1 : 1;
difference *= direction;
for(int c = 0; c < difference; c++) {
get_drive().step(Storage::Disk::HeadPosition(direction));
}
unsigned int zone = 3;
if(track >= 18) zone = 2;
else if(track >= 25) zone = 1;
else if(track >= 31) zone = 0;
set_expected_bit_length(Storage::Encodings::CommodoreGCR::length_of_a_bit_in_time_zone(zone));
}
return get_sector(sector);
}
void set_disk(const std::shared_ptr<Storage::Disk::Disk> &disk) {
get_drive().set_disk(disk);
}
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private:
unsigned int shift_register_;
int index_count_;
int bit_count_;
uint8_t track_;
std::shared_ptr<Sector> sector_cache_[65536];
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void process_input_bit(int value) {
shift_register_ = ((shift_register_ << 1) | unsigned(value)) & 0x3ff;
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bit_count_++;
}
unsigned int proceed_to_next_block(int max_index_count) {
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// find GCR lead-in
proceed_to_shift_value(0x3ff);
if(shift_register_ != 0x3ff) return 0xff;
// find end of lead-in
while(shift_register_ == 0x3ff && index_count_ < max_index_count) {
run_for(Cycles(1));
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}
// continue for a further nine bits
bit_count_ = 0;
while(bit_count_ < 9 && index_count_ < max_index_count) {
run_for(Cycles(1));
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}
return Storage::Encodings::CommodoreGCR::decoding_from_dectet(shift_register_);
}
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unsigned int get_next_byte() {
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bit_count_ = 0;
while(bit_count_ < 10) run_for(Cycles(1));
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return Storage::Encodings::CommodoreGCR::decoding_from_dectet(shift_register_);
}
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void proceed_to_shift_value(unsigned int shift_value) {
const int max_index_count = index_count_ + 2;
while(shift_register_ != shift_value && index_count_ < max_index_count) {
run_for(Cycles(1));
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}
}
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void process_index_hole() {
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index_count_++;
}
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std::shared_ptr<Sector> get_sector(uint8_t sector) {
const uint16_t sector_address = uint16_t((track_ << 8) | sector);
if(sector_cache_[sector_address]) return sector_cache_[sector_address];
const std::shared_ptr<Sector> first_sector = get_next_sector();
if(!first_sector) return first_sector;
if(first_sector->sector == sector) return first_sector;
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while(1) {
const std::shared_ptr<Sector> next_sector = get_next_sector();
if(next_sector->sector == first_sector->sector) return nullptr;
if(next_sector->sector == sector) return next_sector;
}
}
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std::shared_ptr<Sector> get_next_sector() {
auto sector = std::make_shared<Sector>();
const int max_index_count = index_count_ + 2;
while(index_count_ < max_index_count) {
// look for a sector header
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while(1) {
if(proceed_to_next_block(max_index_count) == 0x08) break;
if(index_count_ >= max_index_count) return nullptr;
}
// get sector details, skip if this looks malformed
uint8_t checksum = uint8_t(get_next_byte());
sector->sector = uint8_t(get_next_byte());
sector->track = uint8_t(get_next_byte());
uint8_t disk_id[2];
disk_id[0] = uint8_t(get_next_byte());
disk_id[1] = uint8_t(get_next_byte());
if(checksum != (sector->sector ^ sector->track ^ disk_id[0] ^ disk_id[1])) continue;
// look for the following data
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while(1) {
if(proceed_to_next_block(max_index_count) == 0x07) break;
if(index_count_ >= max_index_count) return nullptr;
}
checksum = 0;
for(std::size_t c = 0; c < 256; c++) {
sector->data[c] = uint8_t(get_next_byte());
checksum ^= sector->data[c];
}
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if(checksum == get_next_byte()) {
uint16_t sector_address = uint16_t((sector->track << 8) | sector->sector);
sector_cache_[sector_address] = sector;
return sector;
}
}
return nullptr;
}
};
std::vector<File> Analyser::Static::Commodore::GetFiles(const std::shared_ptr<Storage::Disk::Disk> &disk) {
std::vector<File> files;
CommodoreGCRParser parser;
parser.set_disk(disk);
// find any sector whatsoever to establish the current track
std::shared_ptr<CommodoreGCRParser::Sector> sector;
// assemble directory
std::vector<uint8_t> directory;
uint8_t next_track = 18;
uint8_t next_sector = 1;
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while(1) {
sector = parser.get_sector(next_track, next_sector);
if(!sector) break;
directory.insert(directory.end(), sector->data.begin(), sector->data.end());
next_track = sector->data[0];
next_sector = sector->data[1];
if(!next_track) break;
}
// parse directory
std::size_t header_pointer = size_t(-32);
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while(header_pointer+32+31 < directory.size()) {
header_pointer += 32;
File new_file;
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switch(directory[header_pointer + 2] & 7) {
case 0: // DEL files
default: continue; // Unknown file types
case 1: new_file.type = File::DataSequence; break;
case 2: new_file.type = File::RelocatableProgram; break; // TODO: need a "don't know about relocatable" program?
case 3: new_file.type = File::User; break;
// case 4: new_file.type = File::Relative; break; // Can't handle REL files yet
}
next_track = directory[header_pointer + 3];
next_sector = directory[header_pointer + 4];
new_file.raw_name.reserve(16);
for(std::size_t c = 0; c < 16; c++) {
new_file.raw_name.push_back(directory[header_pointer + 5 + c]);
}
new_file.name = Storage::Data::Commodore::petscii_from_bytes(&new_file.raw_name[0], 16, false);
std::size_t number_of_sectors = size_t(directory[header_pointer + 0x1e]) + (size_t(directory[header_pointer + 0x1f]) << 8);
new_file.data.reserve((number_of_sectors - 1) * 254 + 252);
bool is_first_sector = true;
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while(next_track) {
sector = parser.get_sector(next_track, next_sector);
if(!sector) break;
next_track = sector->data[0];
next_sector = sector->data[1];
if(is_first_sector) new_file.starting_address = uint16_t(sector->data[2]) | uint16_t(sector->data[3] << 8);
if(next_track)
new_file.data.insert(new_file.data.end(), sector->data.begin() + (is_first_sector ? 4 : 2), sector->data.end());
else
new_file.data.insert(new_file.data.end(), sector->data.begin() + 2, sector->data.begin() + next_sector);
is_first_sector = false;
}
if(!next_track) files.push_back(new_file);
}
return files;
}