ocaml/asmcomp/arm/scheduling.ml

78 lines
2.4 KiB
OCaml

(***********************************************************************)
(* *)
(* OCaml *)
(* *)
(* Benedikt Meurer, University of Siegen *)
(* *)
(* Copyright 1998 Institut National de Recherche en Informatique *)
(* et en Automatique. Copyright 2012 Benedikt Meurer. All rights *)
(* reserved. This file is distributed under the terms of the Q *)
(* Public License version 1.0. *)
(* *)
(***********************************************************************)
open Arch
open Mach
(* Instruction scheduling for the ARM *)
class scheduler = object(self)
inherit Schedgen.scheduler_generic as super
(* Scheduling -- based roughly on the ARM11 (ARMv6) *)
method oper_latency = function
(* Loads have a latency of two cycles in general *)
Iconst_symbol _
| Iconst_float _
| Iload(_, _)
| Ireload
| Ifloatofint (* mcr/mrc count as memory access *)
| Iintoffloat -> 2
(* Multiplys have a latency of two cycles *)
| Iintop (Imul | Imulh)
| Ispecific(Imuladd | Imulsub | Imulhadd) -> 2
(* VFP instructions *)
| Iaddf
| Isubf
| Idivf
| Imulf | Ispecific Inegmulf
| Ispecific(Imuladdf | Inegmuladdf | Imulsubf | Inegmulsubf)
| Ispecific Isqrtf
| Inegf | Iabsf when !fpu >= VFPv2 -> 2
(* Everything else *)
| _ -> 1
method! is_checkbound = function
Ispecific(Ishiftcheckbound _) -> true
| op -> super#is_checkbound op
(* Issue cycles. Rough approximations *)
method oper_issue_cycles = function
Ialloc _ -> 4
| Iintop(Ilsl | Ilsr | Iasr) -> 2
| Iintop(Icomp _)
| Iintop_imm(Icomp _, _) -> 3
| Iintop(Icheckbound)
| Iintop_imm(Icheckbound, _) -> 2
| Ispecific(Ishiftcheckbound _) -> 3
| Iintop(Imul | Imulh)
| Ispecific(Imuladd | Imulsub | Imulhadd) -> 2
(* VFP instructions *)
| Iaddf
| Isubf -> 7
| Imulf
| Ispecific Inegmulf -> 9
| Ispecific(Imuladdf | Inegmuladdf | Imulsubf | Inegmulsubf) -> 17
| Idivf
| Ispecific Isqrtf -> 27
| Inegf | Iabsf | Iconst_float _ when !fpu >= VFPv2 -> 4
(* Everything else *)
| _ -> 1
end
let fundecl f = (new scheduler)#schedule_fundecl f