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

#include"6502.h"

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

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);*/
	P = (x & flag_N) | (P & ~flag_N);
}

//Perform prior to any changes TODO: FIX THIS! WTF WERE YOU THINKING?
void SetFlagV(byte x, byte y){
	address z = (address)x + (address)y;
	if (z > 0xFF)
		SetFlag(flag_V, 1);
	else
		SetFlag(flag_V, 0);
}

/*void SetFlagB(){ //WORK ON
	SetFlag(flag_B, 1);
}*/

/*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);
}

/*void SetFlagC(){
	SetFlag(flag_Z, 1);
}*/


/*byte GetMemory(address x){
	return Memory[x];
}

void SetMemory(address x, byte y){
	Memory[x] = y;
}*/


byte GetStack() {
	S--;
	return GetMemory(0x01FF - S);
}

void SetStack(byte x) {
	SetMemory(0x01FF - S, x);
	S++;
}