ocaml/asmcomp/proc_sparc.ml

(* Description of the Sparc processor *)

open Misc
open Cmm
open Reg
open Arch
open Mach

(* Exceptions raised to signal cases not handled here *)

exception Use_default

(* Recognition of addressing modes *)

type addressing_expr =
    Asymbol of string
  | Alinear of expression
  | Aadd of expression * expression

let rec select_addr = function
    Cconst(Const_symbol s) ->
      (Asymbol s, 0)
  | Cop((Caddi | Cadda), [arg; Cconst(Const_int m)]) ->
      let (a, n) = select_addr arg in (a, n + m)
  | Cop((Caddi | Cadda), [Cconst(Const_int m); arg]) ->
      let (a, n) = select_addr arg in (a, n + m)
  | Cop((Caddi | Cadda), [arg1; arg2]) ->
      begin match (select_addr arg1, select_addr arg2) with
          ((Alinear e1, n1), (Alinear e2, n2)) ->
              (Aadd(e1, e2), n1 + n2)
        | _ ->
              (Aadd(arg1, arg2), 0)
      end
  | exp ->
      (Alinear exp, 0)

let select_addressing exp =
  match select_addr exp with
    (Asymbol s, d) ->
      (Ibased(s, d), Ctuple [])
  | (Alinear e, d) ->
      (Iindexed d, e)
  | (Aadd(e1, e2), d) ->
      (Iindexed2 d, Ctuple[e1; e2])

(* Instruction selection *)

let select_oper op args =
  match (op, args) with
    (Cmuli, [arg1; Cconst(Const_int n)]) ->
      let shift = Misc.log2 n in
      if n = 1 lsl shift
      then (Iintop_imm(Ilsl, shift), arg1)
      else raise Use_default
  | _ ->
      raise Use_default

let pseudoregs_for_operation op arg res = raise Use_default

let is_immediate n = (n <= 4095) & (n >= -4096)

(* Registers available for register allocation *)

(* Register map:
    %l0 - %l7   0 - 7       general purpose, preserved by C
    %o0 - %o5   8 - 13      function results, C functions args / res
    %i0 - %i5   14 - 19     function arguments, preserved by C
    %g2 - %g3   20 - 21     general purpose

    %g1, %g4                temporary
    %g5                     exception pointer
    %g6                     allocation pointer
    %g7                     allocation limit
    %g0                     always zero

    %f0 - %f10  100 - 105   function arguments and results
    %f12 - %f28 106 - 114   general purpose
    %f30                    temporary *)

let int_reg_name = [|
  (* 0-7 *)    "%l0"; "%l1"; "%l2"; "%l3"; "%l4"; "%l5"; "%l6"; "%l7";
  (* 8-13 *)   "%o0"; "%o1"; "%o2"; "%o3"; "%o4"; "%o5";
  (* 14-19 *)  "%i0"; "%i1"; "%i2"; "%i3"; "%i4"; "%i5";
  (* 20-21 *)  "%g2"; "%g3"
|]
  
let float_reg_name = [|
  (* 100-105 *) "%f0"; "%f2"; "%f4"; "%f6"; "%f8"; "%f10";
  (* 106-109 *) "%f12"; "%f14"; "%f16"; "%f18";
  (* 110-114 *) "%f20"; "%f22"; "%f24"; "%f26"; "%f28";
  (* Odd parts of register pairs *)
  (* 115-120 *) "%f1"; "%f3"; "%f5"; "%f7"; "%f9"; "%f11";
  (* 121-124 *) "%f13"; "%f15"; "%f17"; "%f19";
  (* 125-129 *) "%f21"; "%f23"; "%f25"; "%f27"; "%f29"
|]

let num_register_classes = 2

let register_class r =
  match r.typ with
    Int -> 0
  | Addr -> 0
  | Float -> 1

let num_available_registers = [| 22; 15 |]

let first_available_register = [| 0; 100 |]

let register_name r =
  if r < 100 then int_reg_name.(r) else float_reg_name.(r - 100)

(* Representation of hard registers by pseudo-registers *)

let hard_int_reg =
  let v = Array.new 22 Reg.dummy in
  for i = 0 to 21 do v.(i) <- Reg.at_location Int (Reg i) done;
  v

let hard_float_reg =
  let v = Array.new 30 Reg.dummy in
  for i = 0 to 29 do v.(i) <- Reg.at_location Float (Reg(100 + i)) done;
  v

let all_phys_regs =
  Array.append hard_int_reg (Array.sub hard_float_reg 0 15)
  (* No need to include the odd parts of float register pairs *)

let phys_reg n =
  if n < 100 then hard_int_reg.(n) else hard_float_reg.(n - 100)

let stack_slot slot ty =
  Reg.at_location ty (Stack slot)

(* Calling conventions *)

let calling_conventions first_int last_int first_float last_float make_stack
                        arg =
  let loc = Array.new (Array.length arg) Reg.dummy in
  let int = ref first_int in
  let float = ref first_float in
  let ofs = ref 0 in
  for i = 0 to Array.length arg - 1 do
    match arg.(i).typ with
      Int | Addr as ty ->
        if !int <= last_int then begin
          loc.(i) <- phys_reg !int;
          incr int
        end else begin
          loc.(i) <- stack_slot (make_stack !ofs) ty;
          ofs := !ofs + size_int
        end
    | Float ->
        if !float <= last_float then begin
          loc.(i) <- phys_reg !float;
          incr float
        end else begin
          loc.(i) <- stack_slot (make_stack !ofs) Float;
          ofs := !ofs + size_float
        end
  done;
  (loc, Misc.align !ofs 8)         (* Keep stack 8-aligned *)

let incoming ofs = Incoming ofs
let outgoing ofs = Outgoing ofs
let not_supported ofs = fatal_error "Proc.loc_results: cannot call"

let loc_arguments arg =
  calling_conventions 14 19 100 105 outgoing arg
let loc_parameters arg =
  let (loc, ofs) = calling_conventions 14 19 100 105 incoming arg in loc
let loc_results res =
  let (loc, ofs) = calling_conventions 8 13 100 105 not_supported res in loc

(* On the Sparc, all arguments to C functions are passed in %o..%o5,
   even floating-point arguments *)

let ext_calling_conventions arg =
  let loc = Array.new (Array.length arg) Reg.dummy in
  let reg = ref 8 in
  for i = 0 to Array.length arg - 1 do
    if !reg > 13 then
      fatal_error "Proc.ext_calling_conventions: cannot call";
    loc.(i) <- phys_reg !reg;    
    match arg.(i).typ with
      Int | Addr -> incr reg
    | Float -> reg := !reg + 2
  done;
  loc

let loc_external_arguments arg =
  (ext_calling_conventions arg, 0)
let loc_external_results res =
  let (loc, ofs) = calling_conventions 8 8 100 100 not_supported res in loc

let loc_exn_bucket = phys_reg 8         (* $o0 *)

(* Registers destroyed by operations *)

let destroyed_at_call = all_phys_regs
let destroyed_at_raise = all_phys_regs
let destroyed_at_extcall = (* %l0-%l7, %i0-%i5 preserved *)
  Array.of_list(List.map phys_reg
    [0; 1; 2; 3; 4; 5; 6; 7; 14; 15; 16; 17; 18; 19])

let destroyed_at_oper op = [||]

(* Reloading *)

let reload_test makereg tst args = raise Use_default
let reload_operation makereg op args res = raise Use_default

(* Layout of the stack *)
(* Always keep the stack 8-aligned.
   Always leave 96 bytes at the bottom of the stack *)

let num_stack_slots = [| 0; 0 |]
let stack_offset = ref 0
let contains_calls = ref false

let frame_size () =
  let size =
    !stack_offset +
    4 * num_stack_slots.(0) + 8 * num_stack_slots.(1) +
    (if !contains_calls then 8 else 0) in
  Misc.align size 8

let slot_offset loc class =
  match loc with
    Incoming n -> frame_size() + n + 96
  | Local n ->
      if class = 0
      then !stack_offset + n * 4 + 96
      else !stack_offset + num_stack_slots.(0) * 4 + n * 8 + 96
  | Outgoing n -> n + 96