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76 lines
1.4 KiB
C++
76 lines
1.4 KiB
C++
//
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// 1770.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 17/09/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "1770.hpp"
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using namespace WD;
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WD1770::WD1770() : state_(State::Waiting), status_(0), has_command_(false) {}
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void WD1770::set_drive(std::shared_ptr<Storage::Disk::Drive> drive)
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{
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}
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void WD1770::set_is_double_density(bool is_double_density)
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{
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}
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void WD1770::set_register(int address, uint8_t value)
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{
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switch(address&3)
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{
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case 0:
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command_ = value;
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has_command_ = true;
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// TODO: is this force interrupt?
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break;
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case 1: track_ = value; break;
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case 2: sector_ = value; break;
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case 3: data_ = value; break;
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}
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}
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uint8_t WD1770::get_register(int address)
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{
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switch(address&3)
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{
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default: return status_;
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case 1: return track_;
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case 2: return sector_;
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case 3: return data_;
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}
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}
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void WD1770::run_for_cycles(unsigned int number_of_cycles)
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{
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// perform one step every eight cycles, arbitrariy as I can find no timing documentation
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cycles += number_of_cycles;
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while(cycles > 8)
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{
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cycles -= 8;
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switch(state_)
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{
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case State::Waiting:
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if(has_command_)
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{
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has_command_ = false;
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if(command_ & 0x80)
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state_ = (command_ & 0x40) ? State::BeginType3 : State::BeginType2;
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else
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state_ = State::BeginType1;
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}
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continue;
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default:
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printf("Unhandled state %d!", state_);
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return;
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}
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}
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}
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