type stack = Stack of { data : bytes; mutable sp : int }
type mode = Mode of { short : bool; keep : bool; mutable temp : int }

val stack_create : unit -> stack
val peek : mode -> stack -> int
val pop : mode -> stack -> int
val push : mode -> stack -> int -> unit
val pushbyte : mode -> stack -> int -> unit
val pushshort : mode -> stack -> int -> unit
val popbyte : mode -> stack -> int
val popshort : mode -> stack -> int

type machine

val ram : machine -> bytes
val dev : machine -> bytes
val wst : machine -> stack
val rst : machine -> stack

type machine_state = Break | Next of int

type _ Effect.t +=
  | BRK : int Effect.t
  | DEI : ([ `Byte | `Short ] * int) -> int Effect.t
  | DEO : (int * int) -> unit Effect.t
  | Trace : (int * Instr.t * int list) -> unit Effect.t
  | Breakpoint : int -> unit Effect.t

val create : string -> machine
val dispatch : ?trace:bool -> machine -> int -> 'a