open Array;;

type instruction =
  | Reset of int
  | Incr  of int
  | Set   of int*int
  | Jump  of int*int*int;;

type program = instruction array;;

type registers = int array;;

let max_registers = 10000;;

let registres = Array.make (max_registers+1) 0;;

exception Segmentation_fault

exception Memory_exhausted

let next_by_reset ind r = if r <= max_registers then ind+1 else Segmentation_fault;;

let next_by_incr ind r = if r <= max register then ind+1 else  : sig
	
end
let run_instruction regist instruct indice = match instruct with
  | Reset(r)      -> if r <= max_registers then indice+1 else failwith "Segmentation_fault"
  | Incr(r)       -> if i <= max_registers then indice+1 else failwith "Segmentation_fault"
  | Set(r1,r2)    -> if r1 <= max_registers then if r2 <= max_registers then indice+1 else failwith "Segmentation_fault" else failwith "Memory_exhausted"
  | Jump(r1,r2,i) -> if r1 <= max_registers then if r2 <= max_registers then if (Array.get regist r1) = (Array.get regist r2) then i else indice+1 else failwith "Memory_exhausted" else failwith "Memory_exhausted";;

let exec_instruction regist instruct = match instruct with
  | Reset(r)      -> let _ = Array.set regist r 0 in regist
  | Incr(i)       -> let _ = Array.set regist i ((Array.get regist i)+1) in regist
  | Set(r1,r2)    -> let _ = Array.set regist r2 (Array.get regist r1) in regist
  | Jump(r1,r2,i) -> regist;;

let max_steps = 100000;;

let rec step_program regist prog steps = if steps = 0 then regist
                                    else if not ((Array.length prog) = (Array.get regist 0))
                                    then let regist2 = exec_instruction regist (Array.get prog (Array.get regist 0)) in
                                         let nxt = run_instruction regist (Array.get prog (Array.get regist 0)) (Array.get regist 0) in
                                         let _ = Array.set regist2 0 nxt in
                                         step_program regist2 prog (steps-1)
                                     else exec_instruction regist (Array.get prog (Array.get regist 0));;
                                           

let p = Array.of_list [Jump(1,3,5);Incr(2);Incr(3);Jump(1,3,5);Jump(1,1,1);Set(2,0)];;
let r = Array.of_list [0;5;7;0;0;0;0;0];;
                      
let ans = print_int (Array.get (step_program r p max_steps) 0);;
let ans = print_int (Array.get (step_program r p max_steps) 1);;
let ans = print_int (Array.get (step_program r p max_steps) 2);;
let ans = print_int (Array.get (step_program r p max_steps) 3);;
let ans = print_int (Array.get (step_program r p max_steps) 4);;