59 lines
1.6 KiB
C++
59 lines
1.6 KiB
C++
#pragma once
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#include "bus.hh"
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#include "instruction.hh"
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#include "psr.hh"
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#include <cstdint>
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using std::size_t;
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class Cpu {
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public:
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Cpu(Bus& bus);
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void step();
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private:
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static constexpr uint8_t GPR_COUNT = 16;
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static constexpr uint8_t GPR_FIQ_FIRST = 8;
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static constexpr uint8_t GPR_SVC_FIRST = 13;
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static constexpr uint8_t GPR_ABT_FIRST = 13;
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static constexpr uint8_t GPR_IRQ_FIRST = 13;
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static constexpr uint8_t GPR_UND_FIRST = 13;
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static constexpr uint8_t GPR_SYS_USR_FIRST = 8;
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std::shared_ptr<Bus> bus;
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std::array<uint32_t, GPR_COUNT> gpr; // general purpose registers
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Psr cpsr; // current program status register
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Psr spsr; // status program status register
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static constexpr uint8_t PC_INDEX = 15;
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uint32_t& pc = gpr[PC_INDEX];
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bool is_flushed;
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void chg_mode(const Mode to);
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void exec_arm(const arm::ArmInstruction instruction);
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struct {
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std::array<uint32_t, GPR_COUNT - GPR_FIQ_FIRST - 1> fiq;
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std::array<uint32_t, GPR_COUNT - GPR_SVC_FIRST - 1> svc;
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std::array<uint32_t, GPR_COUNT - GPR_ABT_FIRST - 1> abt;
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std::array<uint32_t, GPR_COUNT - GPR_IRQ_FIRST - 1> irq;
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std::array<uint32_t, GPR_COUNT - GPR_UND_FIRST - 1> und;
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// visible registers before the mode switch
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std::array<uint32_t, GPR_COUNT - GPR_SYS_USR_FIRST> old;
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} gpr_banked; // banked general purpose registers
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struct {
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Psr fiq;
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Psr svc;
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Psr abt;
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Psr irq;
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Psr und;
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} spsr_banked; // banked saved program status registers
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};
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