EightBit/inc/Processor.h
Adrian.Conlon 448ee2f09f Refactor the MBC implementation to allow a single point of definition.
Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
2017-08-24 10:28:31 +01:00

95 lines
2.2 KiB
C++

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