diff --git a/hw2/bin/simulator.ml b/hw2/bin/simulator.ml
index 1d5ce5a..0c7de68 100644
--- a/hw2/bin/simulator.ml
+++ b/hw2/bin/simulator.ml
@@ -225,6 +225,7 @@ let fetchins (m : mach) (addr : quad) : ins =
   | _ -> raise InvalidInstructinAlignment
 
 
+exception MalformedOpcodeArgs
 (* Compute the instruction result.
  * NOTE: See int64_overflow.ml for the definition of the return type
 *  Int64_overflow.t. *)
@@ -232,7 +233,26 @@ let interp_opcode (m : mach) (o : opcode) (args : int64 list) : Int64_overflow.t
   let open Int64 in
   let open Int64_overflow in
   match o, args with
-  | _ -> failwith "interp_opcode not implemented"
+  | Negq, [ n ] -> neg n
+  | Incq, [ n ] -> succ n
+  | Decq, [ n ] -> pred n
+  | Addq, [n1; n2] -> add n1 n2
+  | Subq, [n1; n2] -> sub n2 n1
+  | Imulq, [n1; n2] -> mul n1 n2
+  | Notq, [ n ] -> ok @@ lognot n
+  | Andq, [n1; n2] -> ok @@ logand n1 n2
+  | Orq, [n1; n2] -> ok @@ logor n1 n2
+  | Xorq, [n1; n2] -> ok @@ logxor n1 n2
+  | Sarq, [a; n1] -> a |> to_int |> shift_right n1 |> ok
+  | Shrq, [a; n1] -> a |> to_int |> shift_right_logical n1 |> ok
+  | Shlq, [a; n1] -> a |> to_int |> shift_left n1 |> ok
+  | Set c, [ _ ] -> if interp_cnd m.flags c then ok 1L else ok 0L
+  | Leaq, [i; _] -> ok i
+  | Movq, [s; _] -> ok s
+  | Cmpq, [n1; n2] -> sub n2 n1
+  | Jmp, [i] -> ok i
+  | J c, [d] -> if interp_cnd m.flags c then ok d else ok m.regs.(rind Rip)
+  | _ -> raise MalformedOpcodeArgs
 ;;
 
 (** Update machine state with instruction results. *)
@@ -240,9 +260,29 @@ let ins_writeback (m : mach) : ins -> int64 -> unit =
   failwith "ins_writeback not implemented"
 ;;
 
+exception FoundLabelInAsm
+exception NonIndirectOrLabel
+
 (* mem addr ---> mem array index *)
 let interp_operands (m : mach) : ins -> int64 list =
-  failwith "interp_operands not implemented"
+  let inter_value = function
+  | Imm ( Lit q ) -> q
+  | Reg r -> m.regs.(rind r)
+  | Ind1 ( Lit q ) -> readquad m q
+  | Ind2 r -> readquad m m.regs.(rind r)
+  | Ind3 (Lit q, r) -> readquad m @@ m.regs.(rind r) +. q
+  | _ -> raise FoundLabelInAsm
+  in
+  let inter_addr = function
+  | Ind1 (Lit q) -> q
+  | Ind2 r -> m.regs.(rind r)
+  | Ind3 (Lit q, r) -> m.regs.(rind r) +. q
+  | _ -> raise NonIndirectOrLabel
+  in
+  function
+  | Leaq, [i; d] -> [ inter_addr i; inter_value d ]
+  | _, ops -> List.map inter_value ops
+
 ;;
 
 let validate_operands : ins -> unit = function