open import Pervasives_extra
(*open import Sail_impl_base*)
open import Sail2_values
open import Sail2_prompt_monad
open import {isabelle} `Sail2_prompt_monad_lemmas`

val (>>=) : forall 'rv 'a 'b 'e. monad 'rv 'a 'e -> ('a -> monad 'rv 'b 'e) -> monad 'rv 'b 'e
declare isabelle target_rep function (>>=) = infix `\<bind>`
let inline ~{isabelle} (>>=) = bind

val (>>) : forall 'rv 'b 'e. monad 'rv unit 'e -> monad 'rv 'b 'e -> monad 'rv 'b 'e
declare isabelle target_rep function (>>) = infix `\<then>`
let inline ~{isabelle} (>>) m n = m >>= fun (_ : unit) -> n

val iter_aux : forall 'rv 'a 'e. integer -> (integer -> 'a -> monad 'rv unit 'e) -> list 'a -> monad 'rv unit 'e
let rec iter_aux i f xs = match xs with
  | x :: xs -> f i x >> iter_aux (i + 1) f xs
  | [] -> return ()
  end

declare {isabelle} termination_argument iter_aux = automatic

val iteri : forall 'rv 'a 'e. (integer -> 'a -> monad 'rv unit 'e) -> list 'a -> monad 'rv unit 'e
let iteri f xs = iter_aux 0 f xs

val iter : forall 'rv 'a 'e. ('a -> monad 'rv unit 'e) -> list 'a -> monad 'rv unit 'e
let iter f xs = iteri (fun _ x -> f x) xs

val foreachM : forall 'a 'rv 'vars 'e.
  list 'a -> 'vars -> ('a -> 'vars -> monad 'rv 'vars 'e) -> monad 'rv 'vars 'e
let rec foreachM l vars body =
match l with
| [] -> return vars
| (x :: xs) ->
  body x vars >>= fun vars ->
  foreachM xs vars body
end

declare {isabelle} termination_argument foreachM = automatic

val genlistM : forall 'a 'rv 'e. (nat -> monad 'rv 'a 'e) -> nat -> monad 'rv (list 'a) 'e
let genlistM f n =
  let indices = genlist (fun n -> n) n in
  foreachM indices [] (fun n xs -> (f n >>= (fun x -> return (xs ++ [x]))))

val and_boolM : forall 'rv 'e. monad 'rv bool 'e -> monad 'rv bool 'e -> monad 'rv bool 'e
let and_boolM l r = l >>= (fun l -> if l then r else return false)

val or_boolM : forall 'rv 'e. monad 'rv bool 'e -> monad 'rv bool 'e -> monad 'rv bool 'e
let or_boolM l r = l >>= (fun l -> if l then return true else r)

val bool_of_bitU_fail : forall 'rv 'e. bitU -> monad 'rv bool 'e
let bool_of_bitU_fail = function
  | B0 -> return false
  | B1 -> return true
  | BU -> Fail "bool_of_bitU"
end

val bool_of_bitU_nondet : forall 'rv 'e. bitU -> monad 'rv bool 'e
let bool_of_bitU_nondet = function
  | B0 -> return false
  | B1 -> return true
  | BU -> choose_bool "bool_of_bitU"
end

val bools_of_bits_nondet : forall 'rv 'e. list bitU -> monad 'rv (list bool) 'e
let bools_of_bits_nondet bits =
  foreachM bits []
    (fun b bools ->
      bool_of_bitU_nondet b >>= (fun b ->
      return (bools ++ [b])))

val of_bits_nondet : forall 'rv 'a 'e. Bitvector 'a => list bitU -> monad 'rv 'a 'e
let of_bits_nondet bits =
  bools_of_bits_nondet bits >>= (fun bs ->
  return (of_bools bs))

val of_bits_fail : forall 'rv 'a 'e. Bitvector 'a => list bitU -> monad 'rv 'a 'e
let of_bits_fail bits = maybe_fail "of_bits" (of_bits bits)

val mword_nondet : forall 'rv 'a 'e. Size 'a => unit -> monad 'rv (mword 'a) 'e
let mword_nondet () =
  bools_of_bits_nondet (repeat [BU] (integerFromNat size)) >>= (fun bs ->
  return (wordFromBitlist bs))

val whileM : forall 'rv 'vars 'e. 'vars -> ('vars -> monad 'rv bool 'e) ->
                ('vars -> monad 'rv 'vars 'e) -> monad 'rv 'vars 'e
let rec whileM vars cond body =
  cond vars >>= fun cond_val ->
  if cond_val then
    body vars >>= fun vars -> whileM vars cond body
  else return vars

val untilM : forall 'rv 'vars 'e. 'vars -> ('vars -> monad 'rv bool 'e) ->
                ('vars -> monad 'rv 'vars 'e) -> monad 'rv 'vars 'e
let rec untilM vars cond body =
  body vars >>= fun vars ->
  cond vars >>= fun cond_val ->
  if cond_val then return vars else untilM vars cond body

val choose_bools : forall 'rv 'e. string -> nat -> monad 'rv (list bool) 'e
let choose_bools descr n = genlistM (fun _ -> choose_bool descr) n

val choose : forall 'rv 'a 'e. string -> list 'a -> monad 'rv 'a 'e
let choose descr xs =
  (* Use sufficiently many nondeterministically chosen bits and convert into an
     index into the list *)
  choose_bools descr (List.length xs) >>= fun bs ->
  let idx = (natFromNatural (nat_of_bools bs)) mod List.length xs in
  match index xs idx with
    | Just x -> return x
    | Nothing -> Fail ("choose " ^ descr)
  end

declare {isabelle} rename function choose = chooseM

val internal_pick : forall 'rv 'a 'e. list 'a -> monad 'rv 'a 'e
let internal_pick xs = choose "internal_pick" xs

(*let write_two_regs r1 r2 vec =
  let is_inc =
    let is_inc_r1 = is_inc_of_reg r1 in
    let is_inc_r2 = is_inc_of_reg r2 in
    let () = ensure (is_inc_r1 = is_inc_r2)
                    "write_two_regs called with vectors of different direction" in
    is_inc_r1 in

  let (size_r1 : integer) = size_of_reg r1 in
  let (start_vec : integer) = get_start vec in
  let size_vec = length vec in
  let r1_v =
    if is_inc
    then slice vec start_vec (size_r1 - start_vec - 1)
    else slice vec start_vec (start_vec - size_r1 - 1) in
  let r2_v =
    if is_inc
    then slice vec (size_r1 - start_vec) (size_vec - start_vec)
    else slice vec (start_vec - size_r1) (start_vec - size_vec) in
  write_reg r1 r1_v >> write_reg r2 r2_v*)