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CLK/Machines/Electron/Plus3.cpp
Thomas Harte 96648df5fe Ensures all parts of the Electron have a fully-defined initial state.
Specifically to resolve an error with shift being pressed at startup due to a failure to establish a default value for that flag, but applying the same principle across the board.
2017-08-31 22:29:24 -04:00

51 lines
1.3 KiB
C++

//
// Plus3.cpp
// Clock Signal
//
// Created by Thomas Harte on 25/09/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "Plus3.hpp"
using namespace Electron;
Plus3::Plus3() : WD1770(P1770) {
set_control_register(last_control_, 0xff);
}
void Plus3::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
if(!drives_[drive]) {
drives_[drive].reset(new Storage::Disk::Drive);
if(drive == selected_drive_) set_drive(drives_[drive]);
}
drives_[drive]->set_disk(disk);
}
void Plus3::set_control_register(uint8_t control) {
// bit 0 => enable or disable drive 1
// bit 1 => enable or disable drive 2
// bit 2 => side select
// bit 3 => single density select
uint8_t changes = control ^ last_control_;
last_control_ = control;
set_control_register(control, changes);
}
void Plus3::set_control_register(uint8_t control, uint8_t changes) {
if(changes&3) {
switch(control&3) {
case 0: selected_drive_ = -1; set_drive(nullptr); break;
default: selected_drive_ = 0; set_drive(drives_[0]); break;
case 2: selected_drive_ = 1; set_drive(drives_[1]); break;
}
}
if(changes & 0x04) {
invalidate_track();
if(drives_[0]) drives_[0]->set_head((control & 0x04) ? 1 : 0);
if(drives_[1]) drives_[1]->set_head((control & 0x04) ? 1 : 0);
}
if(changes & 0x08) set_is_double_density(!(control & 0x08));
}