(**************************************************************************) (* Sail *) (* *) (* Copyright (c) 2013-2017 *) (* Kathyrn Gray *) (* Shaked Flur *) (* Stephen Kell *) (* Gabriel Kerneis *) (* Robert Norton-Wright *) (* Christopher Pulte *) (* Peter Sewell *) (* Alasdair Armstrong *) (* Brian Campbell *) (* Thomas Bauereiss *) (* Anthony Fox *) (* Jon French *) (* Dominic Mulligan *) (* Stephen Kell *) (* Mark Wassell *) (* *) (* All rights reserved. *) (* *) (* This software was developed by the University of Cambridge Computer *) (* Laboratory as part of the Rigorous Engineering of Mainstream Systems *) (* (REMS) project, funded by EPSRC grant EP/K008528/1. *) (* *) (* Redistribution and use in source and binary forms, with or without *) (* modification, are permitted provided that the following conditions *) (* are met: *) (* 1. Redistributions of source code must retain the above copyright *) (* notice, this list of conditions and the following disclaimer. *) (* 2. Redistributions in binary form must reproduce the above copyright *) (* notice, this list of conditions and the following disclaimer in *) (* the documentation and/or other materials provided with the *) (* distribution. *) (* *) (* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' *) (* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED *) (* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *) (* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR *) (* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, *) (* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT *) (* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF *) (* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND *) (* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, *) (* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT *) (* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF *) (* SUCH DAMAGE. *) (**************************************************************************) open Ast open Ast_util open Type_check open PPrint module Big_int = Nat_big_num let zencode_id = function | Id_aux (Id str, l) -> Id_aux (Id (Util.zencode_string str), l) | Id_aux (DeIid str, l) -> Id_aux (Id (Util.zencode_string ("op " ^ str)), l) let lvar_typ = function | Local (_, typ) -> typ | Register typ -> typ | _ -> assert false (**************************************************************************) (* 1. Conversion to A-normal form (ANF) *) (**************************************************************************) (* The first step in compiling sail is converting the Sail expression grammar into A-normal form. Essentially this converts expressions such as f(g(x), h(y)) into something like: let v0 = g(x) in let v1 = h(x) in f(v0, v1) Essentially the arguments to every function must be trivial, and complex expressions must be let bound to new variables, or used in a block, assignment, or control flow statement (if, for, and while/until loops). The aexp datatype represents these expressions, while aval represents the trivial values. The X_aux construct in ast.ml isn't used here, but the typing information is collapsed into the aexp and aval types. The convention is that the type of an aexp is given by last argument to a constructor. It is omitted where it is obvious - for example all for loops have unit as their type. If some constituent part of the aexp has an annotation, the it refers to the previous argument, so in AE_let (id, typ1, _, body, typ2) typ1 is the type of the bound identifer, whereas typ2 is the type of the whole let expression (and therefore also the body). See Flanagan et al's 'The Essence of Compiling with Continuations' *) type aexp = | AE_val of aval | AE_app of id * aval list * typ | AE_cast of aexp * typ | AE_assign of id * typ * aexp | AE_let of id * typ * aexp * aexp * typ | AE_block of aexp list * aexp * typ | AE_return of aval * typ | AE_if of aval * aexp * aexp * typ | AE_field of aval * id * typ | AE_record_update of aval * aval Bindings.t * typ | AE_for of id * aexp * aexp * aexp * order * aexp | AE_loop of loop * aexp * aexp and aval = | AV_lit of lit * typ | AV_id of id * lvar | AV_ref of id * lvar | AV_tuple of aval list | AV_list of aval list * typ | AV_vector of aval list * typ | AV_C_fragment of string * typ (* Map over all the avals in an aexp. *) let rec map_aval f = function | AE_val v -> AE_val (f v) | AE_cast (aexp, typ) -> AE_cast (map_aval f aexp, typ) | AE_assign (id, typ, aexp) -> AE_assign (id, typ, map_aval f aexp) | AE_app (id, vs, typ) -> AE_app (id, List.map f vs, typ) | AE_let (id, typ1, aexp1, aexp2, typ2) -> AE_let (id, typ1, map_aval f aexp1, map_aval f aexp2, typ2) | AE_block (aexps, aexp, typ) -> AE_block (List.map (map_aval f) aexps, map_aval f aexp, typ) | AE_return (aval, typ) -> AE_return (f aval, typ) | AE_if (aval, aexp1, aexp2, typ2) -> AE_if (f aval, map_aval f aexp1, map_aval f aexp2, typ2) | AE_loop (loop_typ, aexp1, aexp2) -> AE_loop (loop_typ, map_aval f aexp1, map_aval f aexp2) | AE_for (id, aexp1, aexp2, aexp3, order, aexp4) -> AE_for (id, map_aval f aexp1, map_aval f aexp2, map_aval f aexp3, order, map_aval f aexp4) | AE_record_update (aval, updates, typ) -> AE_record_update (f aval, Bindings.map f updates, typ) (* Map over all the functions in an aexp. *) let rec map_functions f = function | AE_app (id, vs, typ) -> f id vs typ | AE_cast (aexp, typ) -> AE_cast (map_functions f aexp, typ) | AE_assign (id, typ, aexp) -> AE_assign (id, typ, map_functions f aexp) | AE_let (id, typ1, aexp1, aexp2, typ2) -> AE_let (id, typ1, map_functions f aexp1, map_functions f aexp2, typ2) | AE_block (aexps, aexp, typ) -> AE_block (List.map (map_functions f) aexps, map_functions f aexp, typ) | AE_if (aval, aexp1, aexp2, typ) -> AE_if (aval, map_functions f aexp1, map_functions f aexp2, typ) | AE_loop (loop_typ, aexp1, aexp2) -> AE_loop (loop_typ, map_functions f aexp1, map_functions f aexp2) | AE_for (id, aexp1, aexp2, aexp3, order, aexp4) -> AE_for (id, map_functions f aexp1, map_functions f aexp2, map_functions f aexp3, order, map_functions f aexp4) | AE_field _ | AE_record_update _ | AE_val _ | AE_return _ as v -> v (* For debugging we provide a pretty printer for ANF expressions. *) let pp_id ?color:(color=Util.green) id = string (string_of_id id |> color |> Util.clear) let pp_lvar lvar doc = match lvar with | Register typ -> string "[R/" ^^ string (string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc | Local (Mutable, typ) -> string "[M/" ^^ string (string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc | Local (Immutable, typ) -> string "[I/" ^^ string (string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc | Enum typ -> string "[E/" ^^ string (string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc | Union (typq, typ) -> string "[U/" ^^ string (string_of_typquant typq ^ "/" ^ string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc | Unbound -> string "[?]" ^^ doc let pp_annot typ doc = string "[" ^^ string (string_of_typ typ |> Util.yellow |> Util.clear) ^^ string "]" ^^ doc let pp_order = function | Ord_aux (Ord_inc, _) -> string "inc" | Ord_aux (Ord_dec, _) -> string "dec" | _ -> assert false (* Order types have been specialised, so no polymorphism in C backend. *) let rec pp_aexp = function | AE_val v -> pp_aval v | AE_cast (aexp, typ) -> pp_annot typ (string "$" ^^ pp_aexp aexp) | AE_assign (id, typ, aexp) -> pp_annot typ (pp_id id) ^^ string " := " ^^ pp_aexp aexp | AE_app (id, args, typ) -> pp_annot typ (pp_id ~color:Util.red id ^^ parens (separate_map (comma ^^ space) pp_aval args)) | AE_let (id, id_typ, binding, body, typ) -> group begin match binding with | AE_let _ -> (pp_annot typ (separate space [string "let"; pp_annot id_typ (pp_id id); string "="]) ^^ hardline ^^ nest 2 (pp_aexp binding)) ^^ hardline ^^ string "in" ^^ space ^^ pp_aexp body | _ -> pp_annot typ (separate space [string "let"; pp_annot id_typ (pp_id id); string "="; pp_aexp binding; string "in"]) ^^ hardline ^^ pp_aexp body end | AE_if (cond, then_aexp, else_aexp, typ) -> pp_annot typ (separate space [ string "if"; pp_aval cond; string "then"; pp_aexp then_aexp; string "else"; pp_aexp else_aexp ]) | AE_block (aexps, aexp, typ) -> pp_annot typ (surround 2 0 lbrace (pp_block (aexps @ [aexp])) rbrace) | AE_return (v, typ) -> pp_annot typ (string "return" ^^ parens (pp_aval v)) | AE_loop (While, aexp1, aexp2) -> separate space [string "while"; pp_aexp aexp1; string "do"; pp_aexp aexp2] | AE_loop (Until, aexp1, aexp2) -> separate space [string "repeat"; pp_aexp aexp2; string "until"; pp_aexp aexp1] | AE_for (id, aexp1, aexp2, aexp3, order, aexp4) -> let header = string "foreach" ^^ space ^^ group (parens (separate (break 1) [ pp_id id; string "from " ^^ pp_aexp aexp1; string "to " ^^ pp_aexp aexp2; string "by " ^^ pp_aexp aexp3; string "in " ^^ pp_order order ])) in header ^//^ pp_aexp aexp4 | AE_field _ -> string "FIELD" | AE_record_update (_, _, typ) -> pp_annot typ (string "RECORD UPDATE") and pp_block = function | [] -> string "()" | [aexp] -> pp_aexp aexp | aexp :: aexps -> pp_aexp aexp ^^ semi ^^ hardline ^^ pp_block aexps and pp_aval = function | AV_lit (lit, typ) -> pp_annot typ (string (string_of_lit lit)) | AV_id (id, lvar) -> pp_lvar lvar (pp_id id) | AV_tuple avals -> parens (separate_map (comma ^^ space) pp_aval avals) | AV_ref (id, lvar) -> string "ref" ^^ space ^^ pp_lvar lvar (pp_id id) | AV_C_fragment (str, typ) -> pp_annot typ (string (str |> Util.cyan |> Util.clear)) | AV_vector (avals, typ) -> pp_annot typ (string "[" ^^ separate_map (comma ^^ space) pp_aval avals ^^ string "]") | AV_list (avals, typ) -> pp_annot typ (string "[|" ^^ separate_map (comma ^^ space) pp_aval avals ^^ string "|]") let ae_lit lit typ = AE_val (AV_lit (lit, typ)) let gensym_counter = ref 0 let gensym () = let id = mk_id ("gs#" ^ string_of_int !gensym_counter) in incr gensym_counter; id let rec split_block = function | [exp] -> [], exp | exp :: exps -> let exps, last = split_block exps in exp :: exps, last | [] -> failwith "empty block" let rec anf (E_aux (e_aux, exp_annot) as exp) = let to_aval = function | AE_val v -> (v, fun x -> x) | AE_app (_, _, typ) | AE_let (_, _, _, _, typ) | AE_return (_, typ) | AE_cast (_, typ) | AE_if (_, _, _, typ) | AE_field (_, _, typ) as aexp -> let id = gensym () in (AV_id (id, Local (Immutable, typ)), fun x -> AE_let (id, typ, aexp, x, typ_of exp)) | AE_assign _ | AE_block _ | AE_for _ | AE_loop _ as aexp -> let id = gensym () in (AV_id (id, Local (Immutable, unit_typ)), fun x -> AE_let (id, unit_typ, aexp, x, typ_of exp)) in match e_aux with | E_lit lit -> ae_lit lit (typ_of exp) | E_block exps -> let exps, last = split_block exps in let aexps = List.map anf exps in let alast = anf last in AE_block (aexps, alast, typ_of exp) | E_assign (LEXP_aux (LEXP_id id, _), exp) -> let aexp = anf exp in AE_assign (id, lvar_typ (Env.lookup_id id (env_of exp)), aexp) | E_loop (loop_typ, cond, exp) -> let acond = anf cond in let aexp = anf exp in AE_loop (loop_typ, acond, aexp) | E_for (id, exp1, exp2, exp3, order, body) -> let aexp1, aexp2, aexp3, abody = anf exp1, anf exp2, anf exp3, anf body in AE_for (id, aexp1, aexp2, aexp3, order, abody) | E_if (cond, then_exp, else_exp) -> let cond_val, wrap = to_aval (anf cond) in let then_aexp = anf then_exp in let else_aexp = anf else_exp in wrap (AE_if (cond_val, then_aexp, else_aexp, typ_of then_exp)) | E_app_infix (x, Id_aux (Id op, l), y) -> anf (E_aux (E_app (Id_aux (DeIid op, l), [x; y]), exp_annot)) | E_app_infix (x, Id_aux (DeIid op, l), y) -> anf (E_aux (E_app (Id_aux (Id op, l), [x; y]), exp_annot)) | E_vector exps -> let aexps = List.map anf exps in let avals = List.map to_aval aexps in let wrap = List.fold_left (fun f g x -> f (g x)) (fun x -> x) (List.map snd avals) in wrap (AE_val (AV_vector (List.map fst avals, typ_of exp))) | E_list exps -> let aexps = List.map anf exps in let avals = List.map to_aval aexps in let wrap = List.fold_left (fun f g x -> f (g x)) (fun x -> x) (List.map snd avals) in wrap (AE_val (AV_list (List.map fst avals, typ_of exp))) | E_field (exp, id) -> let aval, wrap = to_aval (anf exp) in wrap (AE_field (aval, id, typ_of exp)) | E_record_update (exp, FES_aux (FES_Fexps (fexps, _), _)) -> let anf_fexp (FE_aux (FE_Fexp (id, exp), _)) = let aval, wrap = to_aval (anf exp) in (id, aval), wrap in let aval, exp_wrap = to_aval (anf exp) in let fexps = List.map anf_fexp fexps in let wrap = List.fold_left (fun f g x -> f (g x)) (fun x -> x) (List.map snd fexps) in let record = List.fold_left (fun r (id, aval) -> Bindings.add id aval r) Bindings.empty (List.map fst fexps) in exp_wrap (wrap (AE_record_update (aval, record, typ_of exp))) | E_app (id, exps) -> let aexps = List.map anf exps in let avals = List.map to_aval aexps in let wrap = List.fold_left (fun f g x -> f (g x)) (fun x -> x) (List.map snd avals) in wrap (AE_app (id, List.map fst avals, typ_of exp)) | E_throw exp -> let aexp = anf exp in let aval, wrap = to_aval aexp in wrap (AE_app (mk_id "throw", [aval], unit_typ)) | E_exit exp -> let aexp = anf exp in let aval, wrap = to_aval aexp in wrap (AE_app (mk_id "exit", [aval], unit_typ)) | E_return exp -> let aexp = anf exp in let aval, wrap = to_aval aexp in wrap (AE_return (aval, unit_typ)) | E_assert (exp1, exp2) -> let aexp1 = anf exp1 in let aexp2 = anf exp2 in let aval1, wrap1 = to_aval aexp1 in let aval2, wrap2 = to_aval aexp2 in wrap1 (wrap2 (AE_app (mk_id "return", [aval1; aval2], unit_typ))) | E_cons (exp1, exp2) -> let aexp1 = anf exp1 in let aexp2 = anf exp2 in let aval1, wrap1 = to_aval aexp1 in let aval2, wrap2 = to_aval aexp2 in wrap1 (wrap2 (AE_app (mk_id "cons", [aval1; aval2], unit_typ))) | E_id id -> let lvar = Env.lookup_id id (env_of exp) in AE_val (AV_id (id, lvar)) | E_ref id -> let lvar = Env.lookup_id id (env_of exp) in AE_val (AV_ref (id, lvar)) | E_return exp -> let aval, wrap = to_aval (anf exp) in wrap (AE_return (aval, typ_of exp)) | E_var (LEXP_aux (LEXP_id id, _), binding, body) | E_let (LB_aux (LB_val (P_aux (P_id id, _), binding), _), body) -> let env = env_of body in let lvar = Env.lookup_id id env in AE_let (id, lvar_typ lvar, anf binding, anf body, typ_of exp) | E_tuple exps -> let aexps = List.map anf exps in let avals = List.map to_aval aexps in let wrap = List.fold_left (fun f g x -> f (g x)) (fun x -> x) (List.map snd avals) in wrap (AE_val (AV_tuple (List.map fst avals))) | E_cast (typ, exp) -> AE_cast (anf exp, typ) (* Need to think about how to do exception handling *) | E_try _ -> failwith "E_try TODO" | E_vector_access _ | E_vector_subrange _ | E_vector_update _ | E_vector_update_subrange _ | E_vector_append _ -> (* Should be re-written by type checker *) failwith "encountered raw vector operation when converting to ANF" | E_internal_value _ -> (* Interpreter specific *) failwith "encountered E_internal_value when converting to ANF" | E_sizeof _ | E_constraint _ -> (* Sizeof nodes removed by sizeof rewriting pass *) failwith "encountered E_sizeof or E_constraint node when converting to ANF" | E_nondet _ -> (* We don't compile E_nondet nodes *) failwith "encountered E_nondet node when converting to ANF" | _ -> failwith ("Cannot convert to ANF: " ^ string_of_exp exp) (**************************************************************************) (* 2. Converting sail types to C types *) (**************************************************************************) let max_int64 = Big_int.of_int64 Int64.max_int let min_int64 = Big_int.of_int64 Int64.min_int type ctyp = (* Arbitrary precision GMP integer, mpz_t in C. *) | CT_mpz (* Variable length bitvector - flag represents direction, inc or dec *) | CT_bv of bool (* Fixed length bitvector that fits within a 64-bit word. - int represents length, and flag is the same as CT_bv. *) | CT_uint64 of int * bool | CT_int (* Used for (signed) integers that fit within 64-bits. *) | CT_int64 (* unit is a value in sail, so we represent it as a one element type here too for clarity but we actually compile it to an int which is always 0. *) | CT_unit | CT_bool (* Abstractly represent how all the Sail user defined types get mapped into C. We don't fully worry about precise implementation details at this point, as C doesn't have variants or tuples natively, but these need to be encoded. *) | CT_tup of ctyp list | CT_struct of id * ctyp Bindings.t | CT_enum of id * IdSet.t | CT_variant of id * ctyp Bindings.t type ctx = { records : (ctyp Bindings.t) Bindings.t; enums : IdSet.t Bindings.t; variants : (ctyp Bindings.t) Bindings.t; tc_env : Env.t } let initial_ctx env = { records = Bindings.empty; enums = Bindings.empty; variants = Bindings.empty; tc_env = env } let ctyp_equal ctyp1 ctyp2 = match ctyp1, ctyp2 with | CT_mpz, CT_mpz -> true | CT_bv d1, CT_bv d2 -> d1 = d2 | CT_uint64 (m1, d1), CT_uint64 (m2, d2) -> m1 = m2 && d1 = d2 | CT_int, CT_int -> true | CT_int64, CT_int64 -> true | CT_unit, CT_unit -> true | CT_bool, CT_bool -> true | CT_struct (id1, _), CT_struct (id2, _) -> Id.compare id1 id2 = 0 | _, _ -> false let string_of_ctyp = function | CT_mpz -> "mpz_t" | CT_bv true -> "bv_t" | CT_bv false -> "bv_t" | CT_uint64 (n, true) -> "uint64_t<" ^ string_of_int n ^ ", dec>" | CT_uint64 (n, false) -> "uint64_t<" ^ string_of_int n ^ ", int>" | CT_int64 -> "int64_t" | CT_int -> "int" | CT_unit -> "unit" | CT_bool -> "bool" | CT_struct (id, _) -> string_of_id id (* Convert a sail type into a C-type *) let ctyp_of_typ ctx (Typ_aux (typ_aux, _) as typ) = match typ_aux with | Typ_id id when string_of_id id = "bit" -> CT_int | Typ_id id when string_of_id id = "bool" -> CT_bool | Typ_id id when string_of_id id = "int" -> CT_mpz | Typ_app (id, _) when string_of_id id = "range" || string_of_id id = "atom" -> begin match destruct_range typ with | None -> assert false (* Checked if range in guard *) | Some (n, m) -> match nexp_simp n, nexp_simp m with | Nexp_aux (Nexp_constant n, _), Nexp_aux (Nexp_constant m, _) when Big_int.less_equal min_int64 n && Big_int.less_equal m max_int64 -> CT_int64 | _ -> CT_mpz end | Typ_app (id, [Typ_arg_aux (Typ_arg_nexp n, _); Typ_arg_aux (Typ_arg_order ord, _); Typ_arg_aux (Typ_arg_typ (Typ_aux (Typ_id vtyp_id, _)), _)]) when string_of_id id = "vector" && string_of_id vtyp_id = "bit" -> begin let direction = match ord with Ord_aux (Ord_dec, _) -> true | Ord_aux (Ord_inc, _) -> false | _ -> assert false in match nexp_simp n with | Nexp_aux (Nexp_constant n, _) when Big_int.less_equal n (Big_int.of_int 64) -> CT_uint64 (Big_int.to_int n, direction) | _ -> CT_bv direction end | Typ_id id when string_of_id id = "unit" -> CT_unit | Typ_id id when Bindings.mem id ctx.records -> CT_struct (id, Bindings.find id ctx.records) | _ -> failwith ("No C-type for type " ^ string_of_typ typ) let rec is_stack_ctyp ctyp = match ctyp with | CT_uint64 _ | CT_int64 | CT_int | CT_unit | CT_bool -> true | CT_bv _ | CT_mpz -> false | CT_struct (_, fields) -> Bindings.for_all (fun _ ctyp -> is_stack_ctyp ctyp) fields let is_stack_typ ctx typ = is_stack_ctyp (ctyp_of_typ ctx typ) (**************************************************************************) (* 3. Optimization of primitives and literals *) (**************************************************************************) let literal_to_cstring (L_aux (l_aux, _) as lit) = match l_aux with | L_num n when Big_int.less_equal min_int64 n && Big_int.less_equal n max_int64 -> Some (Big_int.to_string n ^ "L") | L_hex str when String.length str <= 16 -> let padding = 16 - String.length str in Some ("0x" ^ String.make padding '0' ^ str ^ "ul") | L_unit -> Some "UNIT" | L_true -> Some "true" | L_false -> Some "false" | _ -> None let c_literals ctx = let c_literal = function | AV_lit (lit, typ) as v when is_stack_ctyp (ctyp_of_typ ctx typ) -> begin match literal_to_cstring lit with | Some str -> AV_C_fragment (str, typ) | None -> v end | v -> v in map_aval c_literal let mask m = if Big_int.less_equal m (Big_int.of_int 64) then let n = Big_int.to_int m in if n mod 4 == 0 then "0x" ^ String.make (16 - n / 4) '0' ^ String.make (n / 4) 'F' ^ "ul" else "0b" ^ String.make (64 - n) '0' ^ String.make n '1' ^ "ul" else failwith "Tried to create a mask literal for a vector greater than 64 bits." let c_aval ctx = function | AV_lit (lit, typ) as v -> begin match literal_to_cstring lit with | Some str -> AV_C_fragment (str, typ) | None -> v end | AV_C_fragment (str, typ) -> AV_C_fragment (str, typ) (* An id can be converted to a C fragment if it's type can be stack-allocated. *) | AV_id (id, lvar) as v -> begin match lvar with | Local (_, typ) when is_stack_typ ctx typ -> AV_C_fragment (string_of_id id, typ) | _ -> v end | AV_tuple avals -> AV_tuple avals let is_c_fragment = function | AV_C_fragment _ -> true | _ -> false let c_fragment_string = function | AV_C_fragment (str, _) -> str | _ -> assert false let analyze_primop' ctx id args typ = let no_change = AE_app (id, args, typ) in (* primops add_range and add_atom *) if string_of_id id = "add_range" || string_of_id id = "add_atom" then begin let n, m, x, y = match destruct_range typ, args with | Some (n, m), [x; y] -> n, m, x, y | _ -> failwith ("add_range has incorrect return type or arity ^ " ^ string_of_typ typ) in match nexp_simp n, nexp_simp m with | Nexp_aux (Nexp_constant n, _), Nexp_aux (Nexp_constant m, _) -> if Big_int.less_equal min_int64 n && Big_int.less_equal m max_int64 then let x, y = c_aval ctx x, c_aval ctx y in if is_c_fragment x && is_c_fragment y then AE_val (AV_C_fragment (c_fragment_string x ^ " + " ^ c_fragment_string y, typ)) else no_change else no_change | _ -> no_change end else if string_of_id id = "xor_vec" then begin let n, x, y = match typ, args with | Typ_aux (Typ_app (id, [Typ_arg_aux (Typ_arg_nexp n, _); _; _]), _), [x; y] when string_of_id id = "vector" -> n, x, y | _ -> failwith ("xor_vec has incorrect return type or arity " ^ string_of_typ typ) in match nexp_simp n with | Nexp_aux (Nexp_constant n, _) when Big_int.less_equal n (Big_int.of_int 64) -> let x, y = c_aval ctx x, c_aval ctx y in if is_c_fragment x && is_c_fragment y then AE_val (AV_C_fragment (c_fragment_string x ^ " ^ " ^ c_fragment_string y, typ)) else no_change | _ -> no_change end else if string_of_id id = "add_vec" then begin let n, x, y = match typ, args with | Typ_aux (Typ_app (id, [Typ_arg_aux (Typ_arg_nexp n, _); _; _]), _), [x; y] when string_of_id id = "vector" -> n, x, y | _ -> failwith ("add_vec has incorrect return type or arity " ^ string_of_typ typ) in match nexp_simp n with | Nexp_aux (Nexp_constant n, _) when Big_int.less_equal n (Big_int.of_int 64) -> let x, y = c_aval ctx x, c_aval ctx y in if is_c_fragment x && is_c_fragment y then AE_val (AV_C_fragment ("(" ^ c_fragment_string x ^ " + " ^ c_fragment_string y ^ ") & " ^ mask n, typ)) else no_change | _ -> no_change end else no_change let analyze_primop ctx id args typ = let no_change = AE_app (id, args, typ) in try analyze_primop' ctx id args typ with | Failure _ -> no_change (**************************************************************************) (* 4. Conversion to low-level AST *) (**************************************************************************) type ctype_def = | CTD_enum of id * IdSet.t | CTD_record of id * ctyp Bindings.t | CTD_variant of id * ctyp Bindings.t type cval = | CV_id of id * ctyp | CV_C_fragment of string * ctyp let cval_ctyp = function | CV_id (_, ctyp) -> ctyp | CV_C_fragment (_, ctyp) -> ctyp type instr = | I_decl of ctyp * id | I_alloc of ctyp * id | I_init of ctyp * id * cval | I_if of cval * instr list * instr list * ctyp | I_funcall of id * id * cval list * ctyp | I_convert of id * ctyp * id * ctyp | I_assign of id * cval | I_copy of id * cval | I_clear of ctyp * id | I_return of id | I_comment of string type cdef = | CDEF_reg_dec of ctyp * id | CDEF_fundef of id * id list * instr list | CDEF_type of ctype_def let pp_ctyp ctyp = string (string_of_ctyp ctyp |> Util.yellow |> Util.clear) let pp_keyword str = string ((str |> Util.red |> Util.clear) ^ "$") and pp_cval = function | CV_id (id, ctyp) -> parens (pp_ctyp ctyp) ^^ (pp_id id) | CV_C_fragment (str, ctyp) -> parens (pp_ctyp ctyp) ^^ (string (str |> Util.cyan |> Util.clear)) let rec pp_instr = function | I_decl (ctyp, id) -> parens (pp_ctyp ctyp) ^^ space ^^ pp_id id | I_if (cval, then_instrs, else_instrs, ctyp) -> let pp_if_block instrs = surround 2 0 lbrace (separate_map hardline pp_instr instrs) rbrace in parens (pp_ctyp ctyp) ^^ space ^^ pp_keyword "IF" ^^ pp_cval cval ^^ pp_keyword "THEN" ^^ pp_if_block then_instrs ^^ pp_keyword "ELSE" ^^ pp_if_block else_instrs | I_alloc (ctyp, id) -> pp_keyword "ALLOC" ^^ parens (pp_ctyp ctyp) ^^ space ^^ pp_id id | I_init (ctyp, id, cval) -> pp_keyword "INIT" ^^ pp_ctyp ctyp ^^ parens (pp_id id ^^ string ", " ^^ pp_cval cval) | I_funcall (x, f, args, ctyp2) -> separate space [ pp_id x; string ":="; pp_id ~color:Util.red f ^^ parens (separate_map (string ", ") pp_cval args); string "->"; pp_ctyp ctyp2 ] | I_convert (x, ctyp1, y, ctyp2) -> separate space [ pp_id x; string ":="; pp_keyword "CONVERT" ^^ pp_ctyp ctyp2 ^^ parens (pp_id y); string "->"; pp_ctyp ctyp1 ] | I_assign (id, cval) -> separate space [pp_id id; string ":="; pp_cval cval] | I_copy (id, cval) -> separate space [string "let"; pp_id id; string "="; pp_cval cval] | I_clear (ctyp, id) -> pp_keyword "CLEAR" ^^ pp_ctyp ctyp ^^ parens (pp_id id) | I_return id -> pp_keyword "RETURN" ^^ pp_id id | I_comment str -> string ("// " ^ str) let compile_funcall ctx id args typ = let setup = ref [] in let cleanup = ref [] in let _, Typ_aux (fn_typ, _) = Env.get_val_spec id ctx.tc_env in let arg_typs, ret_typ = match fn_typ with | Typ_fn (Typ_aux (Typ_tup arg_typs, _), ret_typ, _) -> arg_typs, ret_typ | Typ_fn (arg_typ, ret_typ, _) -> [arg_typ], ret_typ | _ -> assert false in let arg_ctyps, ret_ctyp = List.map (ctyp_of_typ ctx) arg_typs, ctyp_of_typ ctx ret_typ in let final_ctyp = ctyp_of_typ ctx typ in let setup_arg ctyp aval = match aval with | AV_C_fragment (c, typ) -> if is_stack_ctyp ctyp then CV_C_fragment (c, ctyp_of_typ ctx typ) else let gs = gensym () in setup := I_decl (ctyp, gs) :: !setup; setup := I_init (ctyp, gs, CV_C_fragment (c, ctyp_of_typ ctx typ)) :: !setup; cleanup := I_clear (ctyp, gs) :: !cleanup; CV_id (gs, ctyp) | AV_id (id, lvar) -> let have_ctyp = ctyp_of_typ ctx (lvar_typ lvar) in if ctyp_equal ctyp have_ctyp then CV_id (id, ctyp) else if is_stack_ctyp have_ctyp && not (is_stack_ctyp ctyp) then let gs = gensym () in setup := I_decl (ctyp, gs) :: !setup; setup := I_init (ctyp, gs, CV_id (id, have_ctyp)) :: !setup; cleanup := I_clear (ctyp, gs) :: !cleanup; CV_id (gs, ctyp) else CV_id (mk_id ("????" ^ string_of_ctyp (ctyp_of_typ ctx (lvar_typ lvar))), ctyp) | _ -> CV_id (mk_id "???", ctyp) in let sargs = List.map2 setup_arg arg_ctyps args in let call = if ctyp_equal final_ctyp ret_ctyp then fun ret -> I_funcall (ret, id, sargs, ret_ctyp) else if not (is_stack_ctyp ret_ctyp) && is_stack_ctyp final_ctyp then let gs = gensym () in setup := I_alloc (ret_ctyp, gs) :: !setup; setup := I_funcall (gs, id, sargs, ret_ctyp) :: !setup; cleanup := I_clear (ret_ctyp, gs) :: !cleanup; fun ret -> I_convert (ret, final_ctyp, gs, ret_ctyp) else assert false in (List.rev !setup, final_ctyp, call, !cleanup) let rec compile_aexp ctx = function | AE_let (id, _, binding, body, typ) -> let setup, ctyp, call, cleanup = compile_aexp ctx binding in let letb1, letb1c = if is_stack_ctyp ctyp then [I_decl (ctyp, id); call id], [] else [I_alloc (ctyp, id); call id], [I_clear (ctyp, id)] in let letb2 = setup @ letb1 @ cleanup in let setup, ctyp, call, cleanup = compile_aexp ctx body in letb2 @ setup, ctyp, call, cleanup @ letb1c | AE_app (id, vs, typ) -> compile_funcall ctx id vs typ | AE_val (AV_C_fragment (c, typ)) -> let ctyp = ctyp_of_typ ctx typ in [], ctyp, (fun id -> I_copy (id, CV_C_fragment (c, ctyp))), [] | AE_val (AV_id (id, lvar)) -> let ctyp = ctyp_of_typ ctx (lvar_typ lvar) in [], ctyp, (fun id' -> I_copy (id', CV_id (id, ctyp))), [] | AE_val (AV_lit (lit, typ)) -> let ctyp = ctyp_of_typ ctx typ in if is_stack_ctyp ctyp then assert false else let gs = gensym () in [I_alloc (ctyp, gs); I_comment "fix literal init"], ctyp, (fun id -> I_copy (id, CV_id (gs, ctyp))), [I_clear (ctyp, gs)] | AE_if (aval, then_aexp, else_aexp, if_typ) -> let if_ctyp = ctyp_of_typ ctx if_typ in let compile_branch aexp = let setup, ctyp, call, cleanup = compile_aexp ctx aexp in fun id -> setup @ [call id] @ cleanup in let setup, ctyp, call, cleanup = compile_aexp ctx (AE_val aval) in let gs = gensym () in setup @ [I_decl (ctyp, gs); call gs], if_ctyp, (fun id -> I_if (CV_id (gs, ctyp), compile_branch then_aexp id, compile_branch else_aexp id, if_ctyp)), cleanup | AE_record_update (aval, fields, typ) -> let update_field (prev_setup, prev_calls, prev_cleanup) (field, aval) = let setup, _, call, cleanup = compile_aexp ctx (AE_val aval) in prev_setup @ setup, call :: prev_calls, cleanup @ prev_cleanup in let setup, calls, cleanup = List.fold_left update_field ([], [], []) (Bindings.bindings fields) in let ctyp = ctyp_of_typ ctx typ in let gs = gensym () in [I_alloc (ctyp, gs)] @ setup @ List.map (fun call -> call gs) calls, ctyp, (fun id -> I_copy (id, CV_id (gs, ctyp))), cleanup @ [I_clear (ctyp, gs)] | AE_assign (id, assign_typ, aexp) -> (* assign_ctyp is the type of the C variable we are assigning to, ctyp is the type of the C expression being assigned. These may be different. *) let assign_ctyp = ctyp_of_typ ctx assign_typ in let setup, ctyp, call, cleanup = compile_aexp ctx aexp in let unit_fragment = CV_C_fragment ("UNIT", CT_unit) in let comment = "assign " ^ string_of_ctyp assign_ctyp ^ " := " ^ string_of_ctyp ctyp in if ctyp_equal assign_ctyp ctyp then setup @ [call id], CT_unit, (fun id -> I_copy (id, unit_fragment)), cleanup else if not (is_stack_ctyp assign_ctyp) && is_stack_ctyp ctyp then let gs = gensym () in setup @ [ I_comment comment; I_decl (ctyp, gs); call gs; I_convert (id, assign_ctyp, gs, ctyp) ], CT_unit, (fun id -> I_copy (id, unit_fragment)), cleanup else failwith comment | AE_block (aexps, aexp, _) -> let block = compile_block ctx aexps in let setup, ctyp, call, cleanup = compile_aexp ctx aexp in block @ setup, ctyp, call, cleanup | AE_cast (aexp, typ) -> compile_aexp ctx aexp and compile_block ctx = function | [] -> [] | exp :: exps -> let setup, _, call, cleanup = compile_aexp ctx exp in let rest = compile_block ctx exps in let gs = gensym () in setup @ [I_decl (CT_unit, gs); call gs] @ cleanup @ rest let rec pat_ids (P_aux (p_aux, _)) = match p_aux with | P_id id -> [id] | P_tup pats -> List.concat (List.map pat_ids pats) | _ -> failwith "Bad pattern" let compile_type_def ctx (TD_aux (type_def, _)) = match type_def with | TD_enum (id, _, ids, _) -> CTD_enum (id, IdSet.of_list ids), { ctx with enums = Bindings.add id (IdSet.of_list ids) ctx.enums } | TD_record (id, _, _, ctors, _) -> let ctors = List.fold_left (fun ctors (typ, id) -> Bindings.add id (ctyp_of_typ ctx typ) ctors) Bindings.empty ctors in CTD_record (id, ctors), { ctx with records = Bindings.add id ctors ctx.records } | TD_variant (id, _, _, tus, _) -> let compile_tu (Tu_aux (tu_aux, _)) = match tu_aux with | Tu_id id -> CT_unit, id | Tu_ty_id (typ, id) -> ctyp_of_typ ctx typ, id in let ctus = List.fold_left (fun ctus (ctyp, id) -> Bindings.add id ctyp ctus) Bindings.empty (List.map compile_tu tus) in CTD_variant (id, ctus), { ctx with variants = Bindings.add id ctus ctx.variants } (* Will be re-written before here, see bitfield.ml *) | TD_bitfield _ -> failwith "Cannot compile TD_bitfield" (* All type abbreviations will be removed before now. TODO: point to where this is done. *) | TD_abbrev _ -> failwith "Cannot compile TD_abbrev" let compile_def ctx = function | DEF_reg_dec (DEC_aux (DEC_reg (typ, id), _)) -> [CDEF_reg_dec (ctyp_of_typ ctx typ, id)], ctx | DEF_reg_dec _ -> failwith "Unsupported register declaration" (* FIXME *) | DEF_spec _ -> [], ctx | DEF_fundef (FD_aux (FD_function (_, _, _, [FCL_aux (FCL_Funcl (id, pexp), _)]), _)) -> begin match pexp with | Pat_aux (Pat_exp (pat, exp), _) -> let aexp = map_functions (analyze_primop ctx) (c_literals ctx (anf exp)) in print_endline (Pretty_print_sail.to_string (pp_aexp aexp)); let setup, ctyp, call, cleanup = compile_aexp ctx aexp in let gs = gensym () in let instrs = if is_stack_ctyp ctyp then setup @ [I_decl (ctyp, gs); call gs] @ cleanup @ [I_return gs] else assert false in [CDEF_fundef (id, pat_ids pat, instrs)], ctx | _ -> assert false end | DEF_type type_def -> let tdef, ctx = compile_type_def ctx type_def in [CDEF_type tdef], ctx | DEF_default _ -> [], ctx | _ -> assert false (**************************************************************************) (* 5. Code generation *) (**************************************************************************) let sgen_id id = Util.zencode_string (string_of_id id) let codegen_id id = string (sgen_id id) let upper_sgen_id id = Util.zencode_upper_string (string_of_id id) let upper_codegen_id id = string (upper_sgen_id id) let sgen_ctyp = function | CT_unit -> "unit" | CT_int -> "int" | CT_bool -> "bool" | CT_uint64 _ -> "uint64_t" | CT_int64 -> "int64_t" | CT_mpz -> "mpz_t" | CT_bv _ -> "bv_t" | CT_struct (id, _) -> "struct " ^ sgen_id id | CT_enum (id, _) -> "enum " ^ sgen_id id | CT_variant (id, _) -> "struct " ^ sgen_id id let sgen_ctyp_name = function | CT_unit -> "unit" | CT_int -> "int" | CT_bool -> "bool" | CT_uint64 _ -> "uint64_t" | CT_int64 -> "int64_t" | CT_mpz -> "mpz_t" | CT_bv _ -> "bv_t" | CT_struct (id, _) -> sgen_id id | CT_enum (id, _) -> sgen_id id | CT_variant (id, _) -> sgen_id id let sgen_cval = function | CV_C_fragment (c, _) -> c | CV_id (id, _) -> sgen_id id | _ -> "CVAL??" let rec codegen_instr = function | I_decl (ctyp, id) -> string (Printf.sprintf "%s %s;" (sgen_ctyp ctyp) (sgen_id id)) | I_copy (id, cval) -> let ctyp = cval_ctyp cval in if is_stack_ctyp ctyp then string (Printf.sprintf "%s = %s;" (sgen_id id) (sgen_cval cval)) else string (Printf.sprintf "set_%s(%s, %s);" (sgen_ctyp_name ctyp) (sgen_id id) (sgen_cval cval)) | I_if (cval, then_instrs, else_instrs, ctyp) -> string "if" ^^ space ^^ parens (string (sgen_cval cval)) ^^ space ^^ surround 2 0 lbrace (separate_map hardline codegen_instr then_instrs) rbrace ^^ space ^^ string "else" ^^ space ^^ surround 2 0 lbrace (separate_map hardline codegen_instr else_instrs) rbrace | I_funcall (x, f, args, ctyp) -> let args = Util.string_of_list ", " sgen_cval args in if is_stack_ctyp ctyp then string (Printf.sprintf "%s = %s(%s);" (sgen_id x) (sgen_id f) args) else string (Printf.sprintf "%s(%s, %s);" (sgen_id f) (sgen_id x) args) | I_clear (ctyp, id) -> string (Printf.sprintf "clear_%s(%s);" (sgen_ctyp_name ctyp) (sgen_id id)) | I_init (ctyp, id, cval) -> string (Printf.sprintf "init_%s_of_%s(%s, %s);" (sgen_ctyp_name ctyp) (sgen_ctyp_name (cval_ctyp cval)) (sgen_id id) (sgen_cval cval)) | I_alloc (ctyp, id) -> string (Printf.sprintf "%s %s;" (sgen_ctyp ctyp) (sgen_id id)) ^^ hardline ^^ string (Printf.sprintf "init_%s(%s);" (sgen_ctyp_name ctyp) (sgen_id id)) | I_convert (x, ctyp1, y, ctyp2) -> if is_stack_ctyp ctyp1 then string (Printf.sprintf "%s = convert_%s_of_%s(%s);" (sgen_id x) (sgen_ctyp_name ctyp1) (sgen_ctyp_name ctyp2) (sgen_id y)) else string (Printf.sprintf "convert_%s_of_%s(%s, %s);" (sgen_ctyp_name ctyp1) (sgen_ctyp_name ctyp2) (sgen_id x) (sgen_id y)) | I_return id -> string (Printf.sprintf "return %s;" (sgen_id id)) | I_comment str -> string ("/* " ^ str ^ " */") let codegen_type_def ctx = function | CTD_enum (id, ids) -> string (Printf.sprintf "// enum %s" (string_of_id id)) ^^ hardline ^^ separate space [string "enum"; codegen_id id; lbrace; separate_map (comma ^^ space) upper_codegen_id (IdSet.elements ids); rbrace ^^ semi] | CTD_record (id, ctors) -> (* Generate a set_T function for every struct T *) let codegen_set (id, ctyp) = if is_stack_ctyp ctyp then string (Printf.sprintf "rop.%s = op.%s;" (sgen_id id) (sgen_id id)) else string (Printf.sprintf "set_%s(rop.%s, op.%s);" (sgen_ctyp_name ctyp) (sgen_id id) (sgen_id id)) in let codegen_setter id ctors = string (let n = sgen_id id in Printf.sprintf "void set_%s(struct %s rop, const struct %s op)" n n n) ^^ space ^^ surround 2 0 lbrace (separate_map hardline codegen_set (Bindings.bindings ctors)) rbrace in (* Generate an init/clear_T function for every struct T *) let codegen_field_init f (id, ctyp) = if not (is_stack_ctyp ctyp) then [string (Printf.sprintf "%s_%s(op.%s);" f (sgen_ctyp_name ctyp) (sgen_id id))] else [] in let codegen_init f id ctors = string (let n = sgen_id id in Printf.sprintf "void %s_%s(struct %s op)" f n n) ^^ space ^^ surround 2 0 lbrace (separate hardline (Bindings.bindings ctors |> List.map (codegen_field_init f) |> List.concat)) rbrace in (* Generate the struct and add the generated functions *) let codegen_ctor (id, ctyp) = string (sgen_ctyp ctyp) ^^ space ^^ codegen_id id in string (Printf.sprintf "// struct %s" (string_of_id id)) ^^ hardline ^^ string "struct" ^^ space ^^ codegen_id id ^^ space ^^ surround 2 0 lbrace (separate_map (semi ^^ hardline) codegen_ctor (Bindings.bindings ctors) ^^ semi) rbrace ^^ semi ^^ twice hardline ^^ codegen_setter id ctors ^^ twice hardline ^^ codegen_init "init" id ctors ^^ twice hardline ^^ codegen_init "clear" id ctors | CTD_variant (id, tus) -> let codegen_tu (id, ctyp) = separate space [string "struct"; lbrace; string (sgen_ctyp ctyp); codegen_id id ^^ semi; rbrace] in string (Printf.sprintf "// union %s" (string_of_id id)) ^^ hardline ^^ string "enum" ^^ space ^^ string ("kind_" ^ sgen_id id) ^^ space ^^ separate space [lbrace; separate_map (comma ^^ space) (fun id -> string ("Kind_" ^ sgen_id id)) (List.map fst (Bindings.bindings tus)); rbrace ^^ semi] ^^ hardline ^^ hardline ^^ string "struct" ^^ space ^^ codegen_id id ^^ space ^^ surround 2 0 lbrace (separate space [string "enum"; string ("kind_" ^ sgen_id id); string "kind" ^^ semi] ^^ hardline ^^ string "union" ^^ space ^^ surround 2 0 lbrace (separate_map (semi ^^ hardline) codegen_tu (Bindings.bindings tus) ^^ semi) rbrace ^^ semi) rbrace ^^ semi let codegen_def ctx = function | CDEF_reg_dec (ctyp, id) -> string (Printf.sprintf "// register %s" (string_of_id id)) ^^ hardline ^^ string (Printf.sprintf "%s %s;" (sgen_ctyp ctyp) (sgen_id id)) | CDEF_fundef (id, args, instrs) -> List.iter (fun instr -> print_endline (Pretty_print_sail.to_string (pp_instr instr))) instrs; let _, Typ_aux (fn_typ, _) = Env.get_val_spec id ctx.tc_env in let arg_typs, ret_typ = match fn_typ with | Typ_fn (Typ_aux (Typ_tup arg_typs, _), ret_typ, _) -> arg_typs, ret_typ | Typ_fn (arg_typ, ret_typ, _) -> [arg_typ], ret_typ | _ -> assert false in let arg_ctyps, ret_ctyp = List.map (ctyp_of_typ ctx) arg_typs, ctyp_of_typ ctx ret_typ in let args = Util.string_of_list ", " (fun x -> x) (List.map2 (fun ctyp arg -> sgen_ctyp ctyp ^ " " ^ sgen_id arg) arg_ctyps args) in string (sgen_ctyp ret_ctyp) ^^ space ^^ codegen_id id ^^ parens (string args) ^^ hardline ^^ string "{" ^^ jump 2 2 (separate_map hardline codegen_instr instrs) ^^ hardline ^^ string "}" | CDEF_type ctype_def -> codegen_type_def ctx ctype_def let compile_ast ctx (Defs defs) = let chunks, ctx = List.fold_left (fun (chunks, ctx) def -> let defs, ctx = compile_def ctx def in defs :: chunks, ctx) ([], ctx) defs in let cdefs = List.concat (List.rev chunks) in let docs = List.map (codegen_def ctx) cdefs in let preamble = separate hardline [ string "#include \"sail.h\"" ] in let hlhl = hardline ^^ hardline in Pretty_print_sail.to_string (preamble ^^ hlhl ^^ separate hlhl docs) |> print_endline let print_compiled (setup, ctyp, call, cleanup) = List.iter (fun instr -> print_endline (Pretty_print_sail.to_string (pp_instr instr))) setup; print_endline (Pretty_print_sail.to_string (pp_instr (call (mk_id ("?" ^ string_of_ctyp ctyp))))); List.iter (fun instr -> print_endline (Pretty_print_sail.to_string (pp_instr instr))) cleanup let compile_exp ctx exp = let aexp = anf exp in let aexp = c_literals ctx aexp in let aexp = map_functions (analyze_primop ctx) aexp in print_endline "\n###################### COMPILED ######################\n"; print_compiled (compile_aexp ctx aexp); print_endline "\n###################### ANF ######################\n"; aexp (* { uint64_t zx = 0x000000000000F000L; uint64_t v0 = (zx + 0x000000000000000FL) & 0x000000000000FFFFL; uint64_t res = (v0 + 0x000000000000FFFFL) & 0x000000000000FFFFL; return res; } *)