void fetch_instruction(WORD *, WORD *, WORD *);
void dispatch_instruction(WORD, WORD, WORD);
void execute_add(WORD, WORD);
void execute_call(WORD);
void execute_jmp(WORD);
void execute_jze(WORD);
void execute_hlt(void);
void execute_lod(WORD, WORD);
void execute_ret(void);
void execute_sto(WORD, WORD);
void execute_out(WORD, WORD);
void set_cpu_flags(WORD);


UWORD execute_program(void);
WORD check_zero_flag(void);
WORD check_neg_flag(void);