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// 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) ? 1 : 0;
}
void SetFlag(byte flag, int x) {
P = (P & ~flag) | ((x != 0) ? flag : 0);
}
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 ((x & 0x80) != (y & 0x80))
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++;
}
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