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69 lines
1.6 KiB
C++
69 lines
1.6 KiB
C++
//
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// FAT12.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 07/01/2018.
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// Copyright 2018 Thomas Harte. All rights reserved.
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//
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#include "PCBooter.hpp"
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#include "Utility/ImplicitSectors.hpp"
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using namespace Storage::Disk;
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PCBooter::PCBooter(const std::string &file_name) :
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MFMSectorDump(file_name) {
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// The only sanity check here is whether a sensible
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// geometry is encoded in the first sector, or can be guessed.
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const auto file_size = file_.stats().st_size;
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// Check that file size is one of the accepted options.
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switch(file_size) {
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default: throw Error::InvalidFormat;
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case 512 * 8 * 40:
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head_count_ = 1;
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track_count_ = 40;
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sector_count_ = 8;
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break;
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case 512 * 8 * 40 * 2:
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head_count_ = 2;
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track_count_ = 40;
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sector_count_ = 8;
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break;
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case 512 * 9 * 40:
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head_count_ = 1;
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track_count_ = 40;
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sector_count_ = 9;
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break;
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case 512 * 9 * 40 * 2:
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head_count_ = 2;
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track_count_ = 40;
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sector_count_ = 9;
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break;
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}
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// TODO: probably single density, actually?
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set_geometry(sector_count_, 2, 1, Encodings::MFM::Density::Double);
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// TODO: check that an appropriate INT or similar is in the boot sector?
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// Should probably factor out the "does this look like a PC boot sector?" test,
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// as it can also be used to disambiguate FAT12 disks.
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}
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HeadPosition PCBooter::get_maximum_head_position() {
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return HeadPosition(track_count_);
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}
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int PCBooter::get_head_count() {
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return head_count_;
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}
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long PCBooter::get_file_offset_for_position(Track::Address address) {
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return (address.position.as_int() * head_count_ + address.head) * 512 * sector_count_;
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}
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