107 lines
3.6 KiB
OCaml
107 lines
3.6 KiB
OCaml
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(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1997 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Instruction selection for the Power PC processor *)
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open Misc
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open Cmm
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open Reg
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open Arch
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open Mach
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(* Recognition of addressing modes *)
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type addressing_expr =
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Asymbol of string
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| Alinear of expression
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| Aadd of expression * expression
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let rec select_addr = function
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Cconst_symbol s when not toc ->
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(* don't recognize this mode in the TOC-based model *)
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(Asymbol s, 0)
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| Cop((Caddi | Cadda), [arg; Cconst_int m]) ->
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let (a, n) = select_addr arg in (a, n + m)
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| Cop((Caddi | Cadda), [Cconst_int m; arg]) ->
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let (a, n) = select_addr arg in (a, n + m)
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| Cop((Caddi | Cadda), [arg1; arg2]) ->
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begin match (select_addr arg1, select_addr arg2) with
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((Alinear e1, n1), (Alinear e2, n2)) ->
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(Aadd(e1, e2), n1 + n2)
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| _ ->
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(Aadd(arg1, arg2), 0)
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end
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| exp ->
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(Alinear exp, 0)
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(* Instruction selection *)
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class selector () as self =
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inherit Selectgen.selector_generic() as super
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method is_immediate n = (n <= 32767) & (n >= -32768)
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method select_addressing exp =
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match select_addr exp with
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(Asymbol s, d) ->
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(Ibased(s, d), Ctuple [])
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| (Alinear e, d) ->
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(Iindexed d, e)
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| (Aadd(e1, e2), d) ->
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if d = 0
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then (Iindexed2, Ctuple[e1; e2])
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else (Iindexed d, Cop(Cadda, [e1; e2]))
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method select_operation op args =
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match (op, args) with
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(* Prevent the recognition of (x / cst) and (x % cst) when cst is not
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a power of 2, which do not correspond to an instruction. *)
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(Cdivi, [arg; Cconst_int n]) when n = 1 lsl (Misc.log2 n) ->
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(Iintop_imm(Idiv, n), [arg])
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| (Cdivi, _) ->
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(Iintop Idiv, args)
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| (Cmodi, [arg; Cconst_int n]) when n = 1 lsl (Misc.log2 n) ->
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(Iintop_imm(Imod, n), [arg])
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| (Cmodi, _) ->
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(Iintop Imod, args)
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(* The and, or and xor instructions have a different range of immediate
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operands than the other instructions *)
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| (Cand, _) -> self#select_logical Iand args
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| (Cor, _) -> self#select_logical Ior args
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| (Cxor, _) -> self#select_logical Ixor args
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(* intoffloat goes through a library function on the RS6000 *)
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| (Cintoffloat, _) when not powerpc ->
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(Iextcall("itrunc", false), args)
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(* Recognize mult-add and mult-sub instructions *)
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| (Caddf, [Cop(Cmulf, [arg1; arg2]); arg3]) ->
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(Ispecific Imultaddf, [arg1; arg2; arg3])
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| (Caddf, [arg3; Cop(Cmulf, [arg1; arg2])]) ->
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(Ispecific Imultaddf, [arg1; arg2; arg3])
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| (Csubf, [Cop(Cmulf, [arg1; arg2]); arg3]) ->
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(Ispecific Imultsubf, [arg1; arg2; arg3])
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| _ ->
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super#select_operation op args
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method select_logical op = function
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[arg; Cconst_int n] when n >= 0 & n <= 0xFFFF ->
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(Iintop_imm(op, n), [arg])
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| [Cconst_int n; arg] when n >= 0 & n <= 0xFFFF ->
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(Iintop_imm(op, n), [arg])
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| args ->
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(Iintop op, args)
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end
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let fundecl f = (new selector ())#emit_fundecl f
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