(*
Created by Bradley Kovacs
COP 4020 - Summer 2016
Homework 4 - CAM VM
*)

let addOne v =
	v := !v + 1
;;

let subtractOne v =
	v := !v - 1
;;


let maxStackHeight = ref 1000;;
let maxMemLength = ref 1000;;
let maxCodeLength = ref 1000;;
let stack = Array.make !maxStackHeight 0;;
let mem = Array.make !maxMemLength 0;;
let code = Array.make !maxCodeLength 0;;
let sr = ref 0;;
let mr = ref 0;;
let cr = ref 0;;

let load v =
	Array.set stack !sr v
;;

let quote v =
	addOne sr;
	Array.set stack !sr v
;;

let cur l =
	addOne sr;
	Array.set stack !sr l
;;

let dupl () =
	let ele = stack.(!sr) in
	Array.set stack (!sr + 1) ele;
	addOne sr
;;

let swap () =
	let temp1 = stack.(!sr - 1) in
	let temp2 = stack.(!sr) in
	Array.set stack !sr temp1;
	Array.set stack (!sr - 1) temp2
;;

let rot () =
	let temp1 = stack.(!sr - 1) in
	let temp2 = stack.(!sr - 2) in
	let temp3 = stack.(!sr) in
	Array.set stack !sr temp1;
	Array.set stack (!sr - 1) temp2;
	Array.set stack (!sr - 2)  temp3
;;

let irot () =
	let temp1 = stack.(!sr - 2) in
	let temp2 = stack.(!sr) in
	let temp3 = stack.(!sr - 1) in
	Array.set stack !sr temp1;
	Array.set stack (!sr - 1) temp2;
	Array.set stack (!sr - 2) temp3
;;

let plus () =
	let temp1 = stack.(!sr) in
	let temp2 = stack.(!sr - 1) in
	let sum = temp1 + temp2 in
	Array.set stack (!sr - 1) sum;
	subtractOne sr
;;

let mult () =
	let temp1 = stack.(!sr) in
	let temp2 = stack.(!sr - 1) in
	let product = temp1 * temp2 in
	Array.set stack (!sr - 1) product;
	subtractOne sr
;;

let fst () =
	let ele = stack.(!sr) in
	let memEle = mem.(ele) in
	Array.set stack !sr memEle
;;

let snd () =
	let ele = stack.(!sr) in
	let memEle = mem.(ele + 1) in
	Array.set stack !sr memEle
;;

let setfst () =
	let idx = stack.(!sr - 1) in
	Array.set mem idx stack.(!sr);
	subtractOne sr
;;

let setsnd () =
	let idx = (stack.(!sr - 1) + 1) in
	Array.set mem idx stack.(!sr);
	subtractOne sr
;;

let cons () =
	Array.set mem !mr stack.(!sr);
	let ele = stack.(!sr - 1) in
	Array.set mem (!mr + 1) ele;
	Array.set stack (!sr - 1) !mr;
	addOne mr;
	addOne mr;
	subtractOne sr
;;

let split () =
	let ele = mem.(stack.(!sr)) in
	Array.set stack (!sr + 1) ele;
	let ele2 = mem.(stack.(!sr) + 1) in
	Array.set stack !sr ele2;
	subtractOne sr
;;

let branch a1 a2 =
	Array.set stack (!sr) (if stack.(!sr) == 1 then a1 else a2)
;;

let app () =
	let temp = stack.(!sr) in
	Array.set stack !sr stack.(!sr - 1);
	Array.set stack (!sr - 1) (!cr + 1);
	cr := temp
;;

let return () =
	cr := stack.(!sr - 1);
	Array.set stack (!sr - 1) stack.(!sr);
	subtractOne sr
;;


let inputFile = open_in "input.txt" in
try
  while true; do
  	let line = input_line inputFile in
  	print_endline line;

  done;
with End_of_file ->
  close_in inputFile;