//	6502.h
//	Core elements of the 6502 CPU

typedef unsigned char
	byte;
typedef unsigned short
	address;

byte acc, X, Y, P, S = 0x00;
address PC = 0x0000;
byte* Memory;
byte* ROM;

//	FLAGS
#define flag_N 0x80 // Negative
#define flag_V 0x40	// Overflow
#define flag_B 0x10	// BRK command
#define flag_D 0x08	// Decimal mode
#define flag_I 0x04	// IRQ disable
#define flag_Z 0x02	// Zero
#define flag_C 0x01	// Carry

byte getFlag(byte flag) {
	return ((P & flag) == flag) ? 1 : 0;
}

void setFlag(byte flag, int x) {
	if (x == 1){
		if ((P & flag) == 0x0)	P += flag;
	}else if (x == 0){
		if ((P & flag) == flag)	P -= flag;
	}
	else{
		fprintf(stderr, "setFlag() passed arg neither 0 or 1");
	}
}

void flagSet(byte flag){
	P |= flag;
}

void flagClear(byte flag){
	P &= ~flag;
}


//	Functions which perform reusable routines for finding if a specific flag should be set.

void setFlagN(byte x){
	if (x & flag_N == flag_N)
		setFlag(flag_N, 1);
	else
		setFlag(flag_N, 0);
}

//Perform prior to any changes
void setFlagV(byte x, byte y){
	if ((x & flag_N) == (y & flag_N)){
		if (((x + y) & (flag_N ^ 0xFF)) > 0x7F) setFlag(flag_V, 1);
		else setFlag(flag_V, 0);
	}else{
		if (((x - y) & (flag_N ^ 0xFF)) > 0x7F) setFlag(flag_V, 1);
		else setFlag(flag_V, 0);
	}
}

/*void setFlagB(){ //WORK ON
	setFlag(flag_B, 1);
}*/ //Dont really need since its dependent on the BRK insturction

/*void setFlagD(){
	setFlag(flag_D, 1);
}*/

/*void setFlagI(){ //WORK ON
	setFlag(flag_Z, 1);
}*/

void setFlagZ(int x){
	if (x == 0)
		setFlag(flag_Z, 1);
	else
		setFlag(flag_Z, 0);
}

//Only 6 instructions, 2 not including stack instructions, use the carry flag.
// Need to look further into implementation details for this.
/*void setFlagC(){
	setFlag(flag_Z, 1);
}*/


//	Memory Manipulation

// Are to be defined by the system to handle special cases.

byte getMemory(address x);
void setMemory(address x, byte y);







#include"addressing.h"
#include"instructions/definitions.h"
#include"instructions/table.h"