68 lines
1.6 KiB
C++
68 lines
1.6 KiB
C++
#pragma once
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#include <cstdint>
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#include <vector>
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#include <array>
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#include "instruction.h"
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#define MEMORY_SIZE 0x00040000 // 256 kibibytes, or 262144
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#define PROGRAM_ROM_START 0x00001000
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#define GENERAL_PURPOSE_START 0x00010000
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#define PC_REG_OFFSET 7
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#define IHP_REG_OFFSET 8
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#define SP_REG_OFFSET 9
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#define FLAGS_REG_OFFSET 10
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#define PC registers[PC_REG_OFFSET]
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#define IHP registers[PC_REG_OFFSET]
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#define SP registers[PC_REG_OFFSET]
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#define FLAGS registers[PC_REG_OFFSET]
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#define FLAGS_CARRY (1 << 0)
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#define FLAGS_ZERO (1 << 1)
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#define FLAGS_NEGATIVE (1 << 2)
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/*
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* All-purpose memory used by the emulator
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* 4kb for call stack (0x00000000 -> 0x00000FFF)
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* 65kb for program ROM (0x00001000 -> 0x0000FFFF)
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* Rest for general purpose (0x00010000 -> MEMORY_SIZE)
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*/
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struct Memory {
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size_t instructions = 0;
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size_t calls = 0;
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uint8_t memory[MEMORY_SIZE]{};
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void addInstruction(const Instruction& inst);
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void addCall(const uint16_t address);
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uint8_t* operator[](const size_t& offset);
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Memory() = default;
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Memory(const std::vector<Instruction>& instructions) {
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for (const auto& instruction : instructions) {
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addInstruction(instruction.asBytecodeInstruction());
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}
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}
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};
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using Program = std::vector<Instruction>;
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class Emulator {
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private:
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std::array<uint16_t, 11> registers = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
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Memory memory = {};
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bool halted = false;
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Instruction fetchNextInst();
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void updateFlags(int32_t opResult);
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public:
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void start();
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Emulator() = delete;
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Emulator(const Memory& memory) : memory(std::move(memory)) {}
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};
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