mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-11-18 11:06:15 +00:00
95 lines
2.2 KiB
C++
95 lines
2.2 KiB
C++
#pragma once
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#include <cstdint>
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#include "Memory.h"
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namespace EightBit {
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class Processor {
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public:
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enum Masks {
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Mask1 = 0x01,
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Mask2 = 0x03,
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Mask3 = 0x07,
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Mask4 = 0x0f,
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Mask5 = 0x1f,
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Mask6 = 0x3f,
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Mask7 = 0x7f,
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Mask8 = 0xff,
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};
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enum Bits {
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Bit16 = 0x10000,
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Bit15 = 0x8000,
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Bit14 = 0x4000,
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Bit13 = 0x2000,
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Bit12 = 0x1000,
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Bit11 = 0x800,
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Bit10 = 0x400,
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Bit9 = 0x200,
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Bit8 = 0x100,
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Bit7 = 0x80,
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Bit6 = 0x40,
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Bit5 = 0x20,
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Bit4 = 0x10,
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Bit3 = 0x8,
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Bit2 = 0x4,
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Bit1 = 0x2,
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Bit0 = 0x1,
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};
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static int highNibble(int value) { return value >> 4; }
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static int lowNibble(int value) { return value & Mask4; }
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static int promoteNibble(int value) { return value << 4; }
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static int demoteNibble(int value) { return highNibble(value); }
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Memory& getMemory() { return m_memory; }
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register16_t& PC() { return pc; }
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bool isHalted() const { return m_halted; }
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void halt() { --PC().word; m_halted = true; }
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void proceed() { ++PC().word; m_halted = false; }
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virtual void initialise();
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void reset();
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virtual int execute(uint8_t opcode) = 0;
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protected:
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static void clearFlag(uint8_t& f, int flag) { f &= ~flag; }
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static void setFlag(uint8_t& f, int flag) { f |= flag; }
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static void setFlag(uint8_t& f, int flag, int condition) { setFlag(f, flag, condition != 0); }
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static void setFlag(uint8_t& f, int flag, uint32_t condition) { setFlag(f, flag, condition != 0); }
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static void setFlag(uint8_t& f, int flag, bool condition) { condition ? setFlag(f, flag) : clearFlag(f, flag); }
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static void clearFlag(uint8_t& f, int flag, int condition) { clearFlag(f, flag, condition != 0); }
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static void clearFlag(uint8_t& f, int flag, uint32_t condition) { clearFlag(f, flag, condition != 0); }
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static void clearFlag(uint8_t& f, int flag, bool condition) { condition ? clearFlag(f, flag) : setFlag(f, flag); }
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Processor(Memory& memory);
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Memory& m_memory;
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int cycles;
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virtual uint8_t fetchByte() {
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return m_memory.read(PC().word++);
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}
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virtual void fetchWord(register16_t& output) {
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output.low = fetchByte();
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output.high = fetchByte();
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}
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virtual int fetchExecute() {
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return execute(fetchByte());
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}
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private:
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register16_t pc;
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bool m_halted;
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};
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} |