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|
(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1997 Institut National de Recherche en Informatique et *)
(* Automatique. Distributed only by permission. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Instruction selection for the Power PC processor *)
open Misc
open Cmm
open Reg
open Arch
open Mach
(* Recognition of addressing modes *)
type addressing_expr =
Asymbol of string
| Alinear of expression
| Aadd of expression * expression
let rec select_addr = function
Cconst_symbol s when not toc ->
(* don't recognize this mode in the TOC-based model *)
(Asymbol s, 0)
| Cop((Caddi | Cadda), [arg; Cconst_int m]) ->
let (a, n) = select_addr arg in (a, n + m)
| Cop((Caddi | Cadda), [Cconst_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)
(* Instruction selection *)
class selector = object (self)
inherit Selectgen.selector_generic as super
method is_immediate n = (n <= 32767) & (n >= -32768)
method 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) ->
if d = 0
then (Iindexed2, Ctuple[e1; e2])
else (Iindexed d, Cop(Cadda, [e1; e2]))
method select_operation op args =
match (op, args) with
(* Prevent the recognition of (x / cst) and (x % cst) when cst is not
a power of 2, which do not correspond to an instruction. *)
(Cdivi, [arg; Cconst_int n]) when n = 1 lsl (Misc.log2 n) ->
(Iintop_imm(Idiv, n), [arg])
| (Cdivi, _) ->
(Iintop Idiv, args)
| (Cmodi, [arg; Cconst_int n]) when n = 1 lsl (Misc.log2 n) ->
(Iintop_imm(Imod, n), [arg])
| (Cmodi, _) ->
(Iintop Imod, args)
(* The and, or and xor instructions have a different range of immediate
operands than the other instructions *)
| (Cand, _) -> self#select_logical Iand args
| (Cor, _) -> self#select_logical Ior args
| (Cxor, _) -> self#select_logical Ixor args
(* intoffloat goes through a library function on the RS6000 *)
| (Cintoffloat, _) when not powerpc ->
(Iextcall("itrunc", false), args)
(* Recognize mult-add and mult-sub instructions *)
| (Caddf, [Cop(Cmulf, [arg1; arg2]); arg3]) ->
(Ispecific Imultaddf, [arg1; arg2; arg3])
| (Caddf, [arg3; Cop(Cmulf, [arg1; arg2])]) ->
(Ispecific Imultaddf, [arg1; arg2; arg3])
| (Csubf, [Cop(Cmulf, [arg1; arg2]); arg3]) ->
(Ispecific Imultsubf, [arg1; arg2; arg3])
| _ ->
super#select_operation op args
method select_logical op = function
[arg; Cconst_int n] when n >= 0 & n <= 0xFFFF ->
(Iintop_imm(op, n), [arg])
| [Cconst_int n; arg] when n >= 0 & n <= 0xFFFF ->
(Iintop_imm(op, n), [arg])
| args ->
(Iintop op, args)
end
let fundecl f = (new selector)#emit_fundecl f
|
