Simulator started.

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diff --git a/camlsim/machine.ml b/camlsim/machine.ml
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+(* 
+	Système Digital, cours de J.Vuillemin, 2013-2013
+	Alex AUVOLAT, ENS INFO 2013
+
+	Circuit Simulator, machine simulator
+
+	ASSUMPTIONS:
+	- Only one ROM chip
+*)
+
+open Netlist_ast
+
+exception Error of string
+exception Is_not_modified
+
+let load_rom filename =
+	() (* TODO *)
+
+
+type ram_prop = int * int		(* addr size ; word size *)
+type machine = {
+	p				: program;
+	mutable vars	: value Env.t;
+	mutable regs	: value Env.t;
+	ram_chips		: ram_prop array;
+	ram				: value array array;
+}
+
+let rec two_to_the = function
+	| 0 -> 1
+	| n -> let k = (two_to_the (n/2)) in
+		if n mod 2 = 1 then 2 * k else k
+
+let create p =
+	let ram_chips = Array.of_list
+		(List.fold_left
+			(fun x (_, v) -> match v with
+			| Eram (a, w, _, _, _, _) ->
+				(a, w)::x
+			| _ -> x)
+			[]
+			p.p_eqs) in
+	let vars = Env.fold
+			(fun k v x -> 
+				Env.add k
+					(match v with
+						| TBit -> VBit(false)
+						| TBitArray(n) -> VBitArray(Array.make n false))
+					x)
+			p.p_vars
+			Env.empty in
+	{ 
+		p = p;
+		vars = vars;
+		regs = Env.empty;	(* no use putting anything at the moment *)
+		ram_chips = ram_chips;
+		ram = Array.map
+			(fun (a, w) -> Array.make (two_to_the a) (VBitArray (Array.make w false)))
+			ram_chips;
+	}
+
+let read_inputs m f =
+	List.iter
+		(fun n ->
+			m.vars <- Env.add n (f (n, Env.find n m.p.p_vars)) m.vars)
+		m.p.p_inputs
+
+let step m =
+	let get = function
+	| Avar(x) -> 
+		begin match Env.find x m.vars with
+		| VBit(x) -> VBit(x)
+		| VBitArray(u) as s ->
+			if Array.length u = 1 then VBit(u.(0)) else s
+		end
+	| Aconst(x) -> x
+	in
+	(* Load register values into dest variables *)
+	Env.iter
+		(fun k v ->
+			m.vars <- Env.add k v m.vars)
+		m.regs;
+	(* Do all the logic *)
+	List.iter
+		(fun (varname, exp) ->
+			let evaluate = function
+			| Earg(k) -> get k
+			| Ereg(_) -> raise Is_not_modified	(* do nothing, registers are handled somewhere else *)
+			| Enot(k) -> 
+				begin match get k with
+				| VBit(u) -> VBit (not u)
+				| VBitArray(u) -> VBitArray(Array.map (fun x -> not x) u)
+				end
+			| Ebinop(op, k1, k2) ->
+				let f = begin match op with
+				| Or -> (fun x y -> x || y)
+				| Xor -> (fun x y -> (x || y) && (not (x && y)))
+				| And -> (fun x y -> x && y)
+				| Nand -> (fun x y -> not (x && y))
+				end in
+				begin match get k1, get k2 with
+				| VBit(u), VBit(v) -> VBit(f u v)
+				| VBitArray(u), VBitArray(v) when Array.length u = Array.length v ->
+					let r = Array.make (Array.length u) false in
+					for i = 0 to Array.length u - 1 do
+						r.(i) <- (f u.(i) v.(i))
+					done; VBitArray(r)
+				| VBit(u), VBitArray(v) -> VBit(f u v.(0))
+				| VBitArray(u), VBit(v) -> VBit(f u.(0) v)
+				| _ -> raise (Error "Incompatible data types.")
+				end
+			| Emux (control, in0, in1) ->
+				begin match get control, get in0, get in1 with
+				| VBit(u), x, y ->
+					if u then y else x
+				| VBitArray(u), VBitArray(a), VBitArray(b)
+					when Array.length a = Array.length b
+					&& Array.length u = Array.length a ->
+					let r = Array.make (Array.length u) false in
+					for i = 0 to Array.length u - 1 do
+						r.(i) <- (if u.(i) then b.(i) else a.(i))
+					done;
+					VBitArray(r)
+				| _ -> raise (Error "Invalid data size in mux")
+				end
+			| Erom(_, w, _) -> VBitArray(Array.make w false) (* TODO *)
+			| Eram(_, _, _,_, _, _) -> raise Is_not_modified (* TODO *)
+			| Econcat(k1, k2) ->
+				let a1 = match get k1 with
+				| VBit(u) -> [|u|]
+				| VBitArray(u) -> u
+				in
+				let a2 = match get k2 with
+				| VBit(u) -> [|u|]
+				| VBitArray(u) -> u
+				in
+				VBitArray(Array.append a1 a2)
+			| Eslice (first, last, k) ->
+				begin match get k with
+				| VBit(u) when first = 0 && last = 0 -> VBit(u)
+				| VBitArray(u) ->
+					let r = Array.make (last - first) false in
+					for i = first to last - 1 do
+						r.(i - first) <- u.(i)
+					done;
+					VBitArray(u)
+				| _ -> raise (Error "Invalid slicing parameters")
+				end
+			| Eselect(id, k) ->
+				begin match get k with
+				| VBit(u) when id = 0 -> VBit(u)
+				| VBitArray(u) -> VBit(u.(id))
+				| _ -> raise (Error "Invalid select parameters")
+				end
+			in
+			try
+				m.vars <- Env.add varname (evaluate exp) m.vars
+			with Is_not_modified -> ())
+		m.p.p_eqs;
+	(* Saves register values *)
+	m.regs <- List.fold_left
+		(fun x (k, v) ->
+			match v with
+			| Ereg(n) -> Env.add k (Env.find n m.vars) x
+			| _ -> x)
+		Env.empty
+		m.p.p_eqs
+
+let print_outputs m f =
+	List.iter
+		(fun n ->
+			f (n, Env.find n m.vars))
+		m.p.p_outputs
+