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118 lines
3.2 KiB
C++
118 lines
3.2 KiB
C++
//
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// Amiga.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 16/07/2021.
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// Copyright © 2021 Thomas Harte. All rights reserved.
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//
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#include "Amiga.hpp"
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#include "../MachineTypes.hpp"
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#include "../../Processors/68000/68000.hpp"
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#include "../../Analyser/Static/Amiga/Target.hpp"
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#include "../Utility/MemoryPacker.hpp"
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#include "../Utility/MemoryFuzzer.hpp"
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namespace Amiga {
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class ConcreteMachine:
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public CPU::MC68000::BusHandler,
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public MachineTypes::ScanProducer,
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public MachineTypes::TimedMachine,
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public Machine {
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public:
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ConcreteMachine(const Analyser::Static::Amiga::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
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mc68000_(*this)
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{
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(void)target;
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// Temporary: use a hard-coded Kickstart selection.
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constexpr ROM::Name rom_name = ROM::Name::AmigaA500Kickstart13;
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ROM::Request request(rom_name);
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auto roms = rom_fetcher(request);
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if(!request.validate(roms)) {
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throw ROMMachine::Error::MissingROMs;
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}
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Memory::PackBigEndian16(roms.find(rom_name)->second, kickstart_.data());
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// NTSC clock rate: 2*3.579545 = 7.15909Mhz.
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// PAL clock rate: 7.09379Mhz.
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set_clock_rate(7'093'790.0);
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}
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// MARK: - MC68000::BusHandler.
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using Microcycle = CPU::MC68000::Microcycle;
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HalfCycles perform_bus_operation(const CPU::MC68000::Microcycle &cycle, int) {
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// Do nothing if no address is exposed.
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if(!(cycle.operation & (Microcycle::NewAddress | Microcycle::SameAddress))) return HalfCycles(0);
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// TODO: interrupt acknowledgement though?
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// Grab the target address to pick a memory source.
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const uint32_t address = cycle.host_endian_byte_address();
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(void)address;
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// Address spaces that matter:
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//
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// 00'0000 – 08'0000: chip RAM. [or overlayed KickStart]
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// – 10'0000: extended chip ram for ECS.
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// – 20'0000: auto-config space (/fast RAM).
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// ...
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// bf'd000 – c0'0000: 8250s.
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// c0'0000 – d8'0000: pseudo-fast RAM.
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// ...
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// dc'0000 – dd'0000: optional real-time clock.
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// df'f000 - e0'0000: custom chip registers.
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// ...
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// f0'0000 — : 512kb Kickstart (or possibly just an extra 512kb reserved for hypothetical 1mb Kickstart?).
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// f8'0000 — : 256kb Kickstart if 2.04 or higher.
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// fc'0000 – : 256kb Kickstart otherwise.
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return HalfCycles(0);
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}
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private:
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CPU::MC68000::Processor<ConcreteMachine, true> mc68000_;
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// MARK: - Memory map.
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std::array<uint8_t, 512*1024> ram_;
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std::array<uint8_t, 512*1024> kickstart_;
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struct MemoryRegion {
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} regions_[64]; // i.e. top six bits are used as an index.
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// MARK: - MachineTypes::ScanProducer.
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void set_scan_target(Outputs::Display::ScanTarget *scan_target) final {
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(void)scan_target;
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}
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Outputs::Display::ScanStatus get_scaled_scan_status() const {
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return Outputs::Display::ScanStatus();
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}
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// MARK: - MachineTypes::TimedMachine.
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void run_for(const Cycles cycles) {
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mc68000_.run_for(cycles);
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}
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};
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}
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using namespace Amiga;
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Machine *Machine::Amiga(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
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using Target = Analyser::Static::Amiga::Target;
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const Target *const amiga_target = dynamic_cast<const Target *>(target);
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return new Amiga::ConcreteMachine(*amiga_target, rom_fetcher);
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}
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Machine::~Machine() {}
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