84 lines
2.5 KiB
OCaml
84 lines
2.5 KiB
OCaml
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module Types = Types
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open Types
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let do_local state i f =
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match List.nth_opt state.env i with
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| None -> failwith "Invalid index for local access"
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| Some x -> f x
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let load_local state i =
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do_local state i (!)
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let set_local state i v =
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do_local state i (fun r -> r := v)
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let pop_one state =
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match state.stack with
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| v :: rest -> state.stack <- rest; v
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| [] -> failwith ("VM error: cannot pop from empty stack! " ^ (string_of_int state.i))
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let push state v =
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state.stack <- (v :: state.stack)
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let rec do_apply state =
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let cur_env = state.env in
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let cur_i = state.i in
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let arg = pop_one state in
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let f = pop_one state in
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match f with
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| Closure (x, e) ->
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state.call_stack <- (cur_i, cur_env) :: state.call_stack;
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state.i <- x;
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state.env <- (ref arg) :: e;
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interpret state
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| Native x ->
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push state (Native.table.(x) arg)
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| _ -> failwith "Cannot apply non-closure object"
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and interpret state =
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(match state.stack with
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| [] -> print_endline "empty"
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| _ -> print_endline "nonempty");
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let i = state.i in
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state.i <- i + 1;
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(match state.instrs.(i) with
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| Constant x -> push state state.constants.(x) ; interpret state
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| LoadLocal x -> push state (load_local state x) ; interpret state
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| LoadGlobal x -> push state state.globals.(x) ; interpret state
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| StoreLocal x -> set_local state x (pop_one state) ; interpret state
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| StoreGlobal x -> Array.set state.globals x (pop_one state) ; interpret state
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| MakeCons ->
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let cdr = pop_one state in
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let car = pop_one state in
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push state (Cons (car, cdr))
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| Pop -> ignore (pop_one state) ; interpret state
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| Apply -> do_apply state
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| MakeClosure x -> push state (Closure (x, state.env)); interpret state
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| Jump target -> state.i <- target ; interpret state
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| JumpF target ->
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(match (pop_one state) with
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| Nil -> state.i <- target
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| _ -> ()); interpret state
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| End ->
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(match state.call_stack with
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| [] ->
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print_endline "\nPROGRAM HAS SUCCESSFULLY TERMINATED\n"
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| (old_i, old_env) :: rest ->
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state.call_stack <- rest;
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state.env <- old_env;
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state.i <- old_i;
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interpret state)
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| NOOP -> interpret state)
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let make_vm instrs constants global_count =
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let globals = Array.init global_count (fun x -> if x < (Array.length Native.table) then Native x else Nil) in
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{
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i = 0;
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instrs = instrs;
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globals = globals;
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constants = constants;
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env = [];
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stack = [];
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call_stack = [];
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}
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