91 lines
2.7 KiB
OCaml
91 lines
2.7 KiB
OCaml
exception Runtime_error of string
|
|
|
|
module Op = struct
|
|
let add v1 v2 =
|
|
match v1, v2 with
|
|
| Value.Int x, Value.Int y -> Value.Int (Int64.add x y)
|
|
| _, _ -> raise (Runtime_error "cannot add non integer values")
|
|
|
|
let sub v1 v2 =
|
|
match v1, v2 with
|
|
| Value.Int x, Value.Int y -> Value.Int (Int64.sub x y)
|
|
| _, _ -> raise (Runtime_error "cannot sub non integer values")
|
|
|
|
let mul v1 v2 =
|
|
match v1, v2 with
|
|
| Value.Int x, Value.Int y -> Value.Int (Int64.mul x y)
|
|
| _, _ -> raise (Runtime_error "cannot mul non integer values")
|
|
|
|
let eql v1 v2 =
|
|
match v1, v2 with
|
|
| Value.Int x, Value.Int y -> Value.bool (Int64.equal x y)
|
|
| _, _ -> Value.bool (v1 == v2)
|
|
|
|
let lst v1 v2 =
|
|
match v1, v2 with
|
|
| Value.Int x, Value.Int y -> Value.bool (Int64.compare x y < 0)
|
|
| _, _ -> raise (Runtime_error "cannot compare non integer values")
|
|
|
|
let truthy = function
|
|
| Value.False | Value.Nil -> false
|
|
| _ -> true
|
|
|
|
let not v = Value.bool (not (truthy v))
|
|
|
|
let get o s =
|
|
match o, s with
|
|
| Value.Obj (_, slots), Value.Int i -> slots.(Int64.to_int i)
|
|
| _ -> raise (Runtime_error "get field of non-object")
|
|
|
|
let set o s v =
|
|
match o, s with
|
|
| Value.Obj (_, slots), Value.Int i -> slots.(Int64.to_int i) <- v
|
|
| _ -> raise (Runtime_error "set field of non-object")
|
|
end
|
|
|
|
type frame = {
|
|
regs : Value.t array;
|
|
mutable pc : Code.ins list;
|
|
}
|
|
|
|
let make_frame prog =
|
|
{
|
|
regs = Array.make (Code.frame_size prog) Value.Nil;
|
|
pc = Code.instructions Code.(prog.entrypoint);
|
|
}
|
|
|
|
let return_value fr = fr.regs.(0)
|
|
|
|
let eval fr = function
|
|
| Code.Cst_nil -> Value.Nil
|
|
| Code.Cst_true -> Value.Nil
|
|
| Code.Cst_false -> Value.Nil
|
|
| Code.Cst_int n -> Value.Int n
|
|
| Code.Reg i -> fr.regs.(i)
|
|
|
|
let exec fr = function
|
|
| Code.MOV (l, r) -> fr.regs.(l) <- eval fr r
|
|
| Code.ADD (l, r) -> fr.regs.(l) <- Op.add fr.regs.(l) (eval fr r)
|
|
| Code.SUB (l, r) -> fr.regs.(l) <- Op.add fr.regs.(l) (eval fr r)
|
|
| Code.MUL (l, r) -> fr.regs.(l) <- Op.mul fr.regs.(l) (eval fr r)
|
|
| Code.EQL (l, r) -> fr.regs.(l) <- Op.eql fr.regs.(l) (eval fr r)
|
|
| Code.LST (l, r) -> fr.regs.(l) <- Op.lst fr.regs.(l) (eval fr r)
|
|
| Code.NOT l -> fr.regs.(l) <- Op.not fr.regs.(l)
|
|
| Code.CON (l, vt) -> fr.regs.(l) <- Value.make_obj vt
|
|
| Code.GET (o, s) -> fr.regs.(s) <- Op.get fr.regs.(o) fr.regs.(s)
|
|
| Code.SET (o, s) -> Op.set fr.regs.(o) fr.regs.(s) fr.regs.(s + 1)
|
|
| Code.RET -> fr.pc <- []
|
|
| Code.JMP l -> fr.pc <- Code.instructions l
|
|
| Code.CBR (v, l1, l2) ->
|
|
fr.pc <- Code.instructions (if Op.truthy (eval fr v) then l1 else l2)
|
|
|
|
let rec run fr =
|
|
match fr.pc with
|
|
| [] -> return_value fr
|
|
| is :: rest ->
|
|
fr.pc <- rest;
|
|
exec fr is;
|
|
run fr
|
|
|
|
let run_program pr = run (make_frame pr)
|