cpu.h

/*
Copyright (c) 2019, Mahmoud N. Jaoune
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the <organization> nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef _CPU_H_
#define _CPU_H_

#include <vector>
#include "ram.h"
#include "rom.h"
#include "flash.h"
#include "interrupts.h"
#include "bitwisemath.h"

class VE_VMS_CPU
{
public:

	int state;   //0: stopped. 1: started.
	int EXTOld;
    int EXTNew;
    bool P3_taken;

	VE_VMS_CPU(VE_VMS_RAM *_ram, VE_VMS_ROM *_rom, VE_VMS_FLASH *_flash, VE_VMS_INTERRUPTS *_intHandler, bool hle);
	~VE_VMS_CPU();
	
	double getCurrentFrequency();
	void setFrequency(double f);

	//Memory operations
	//Reads a byte either from ROM or Flash, depending on value of EXT
	byte readByteRF(size_t address);
	
	//Writes a byte either from ROM or Flash, depending on value of EXT
	void writeByteRF(size_t address, byte d);
	
	
	//Read
	byte *readFromROM(size_t address, size_t byteCount);
	byte *readFromRAM(size_t address, size_t byteCount);
	
	//Write
	void writeToROM(byte *data, size_t dataSize, size_t address);
	void writeToRAM(byte *data, size_t dataSize, size_t address);
	
	//Address/Data functions
	//Immediate
	byte getAddress_i8();
	
	//Relative 8-bit (signed)
	signed char getAddress_r8();
	
	//Relative 8-bit when the opcode has bit specifiers (signed)
	signed char getAddress_r8_b3();
	
	//Relative 16-bit
	size_t getAddress_r16();
	
	//Direct 9-bit
	size_t getAddress_d9();
	
	//Direct 9-bit with bit assignment
	size_t getAddress_d9_b3();
	
	//Get bits (b3)
	byte getAddress_b3();
	
	//Indirect
	size_t getAddress_R();
	
	//Absolute 12-bit
	size_t getAddress_a12();
	
	//Absolute 16-bit
	size_t getAddress_a16();
	
	//Absolute 16-bit (But can select to get operand from ROM (EXT = 0) or Flash (EXT = 1), important for when an instruction changes EXT, it will always be followed by a JMPF)
	size_t getAddress_a16(byte _EXT);

    //FLAG operations
    void FLAG_setP();
    
    void FLAG_clearP();
    
    byte FLAG_getP();
    
    void FLAG_setOV();
    
    void FLAG_clearOV();
    
    byte FLAG_getOV();
    
    void FLAG_setAC();
    
    void FLAG_clearAC();
    
    byte FLAG_getAC();
    
    void FLAG_setCY();
    
    void FLAG_clearCY();
    
    byte FLAG_getCY();


    /******************************************************
     ******************************************************
     *  Instructions and interrupts
     ******************************************************
     ******************************************************/

    void processInterrupts();

    void performHLE(size_t entryAddress);

	//Interpreter
    int processInstruction(bool dbg);
    
private:
    size_t PC; //This counts where we reached in instruction memory (Starting from first instruction executed)
    int clock;   //In nanoseconds
    double frequency;
    int interruptLevel;
    int currentInterrupt;
    bool interruptsMasked;

    int instructionCount;
    
    VE_VMS_RAM *ram;
    VE_VMS_ROM *rom;
    VE_VMS_FLASH *flash;
    VE_VMS_INTERRUPTS *intHandler;
    
    std::vector<int> interruptQueue;
    
    bool IsHLE;
};

#endif // _CPU_H_