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|
(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Description of the Intel 386 processor *)
open Misc
open Arch
open Formatmsg
open Cmm
open Reg
open Mach
(* Registers available for register allocation *)
(* Register map:
eax 0 eax - edi: function arguments and results
ebx 1 eax: C function results
ecx 2 ebx, esi, edi, ebp: preserved by C
edx 3
esi 4
edi 5
ebp 6
tos 100 top of floating-point stack. *)
let int_reg_name =
[| "%eax"; "%ebx"; "%ecx"; "%edx"; "%esi"; "%edi"; "%ebp" |]
let float_reg_name =
[| "%tos" |]
let num_register_classes = 2
let register_class r =
match r.typ with
Int -> 0
| Addr -> 0
| Float -> 1
let num_available_registers = [| 7; 0 |]
let first_available_register = [| 0; 100 |]
let register_name r =
if r < 100 then int_reg_name.(r) else float_reg_name.(r - 100)
(* There is little scheduling, and some operations are more compact
when their argument is %eax. *)
let rotate_registers = false
(* Representation of hard registers by pseudo-registers *)
let hard_int_reg =
let v = Array.create 7 Reg.dummy in
for i = 0 to 6 do v.(i) <- Reg.at_location Int (Reg i) done;
v
let hard_float_reg = [| Reg.at_location Float (Reg 100) |]
let all_phys_regs =
Array.append hard_int_reg hard_float_reg
let phys_reg n =
if n < 100 then hard_int_reg.(n) else hard_float_reg.(n - 100)
let eax = phys_reg 0
let ecx = phys_reg 2
let edx = phys_reg 3
let tos = phys_reg 100
let stack_slot slot ty =
Reg.at_location ty (Stack slot)
(* Instruction selection *)
let word_addressed = false
(* Calling conventions *)
let calling_conventions first_int last_int first_float last_float make_stack
arg =
let loc = Array.create (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, !ofs)
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 0 5 100 99 outgoing arg
let loc_parameters arg =
let (loc, ofs) = calling_conventions 0 5 100 99 incoming arg in loc
let loc_results res =
let (loc, ofs) = calling_conventions 0 5 100 100 not_supported res in loc
let extcall_use_push = true
let loc_external_arguments arg =
fatal_error "Proc.loc_external_arguments"
let loc_external_results res =
let (loc, ofs) = calling_conventions 0 0 100 100 not_supported res in loc
let loc_exn_bucket = eax
(* Registers destroyed by operations *)
let destroyed_at_c_call = (* ebx, esi, edi, ebp preserved *)
[|eax; ecx; edx|]
let destroyed_at_oper = function
Iop(Icall_ind | Icall_imm _ | Iextcall(_, true)) -> all_phys_regs
| Iop(Iextcall(_, false)) -> destroyed_at_c_call
| Iop(Iintop(Idiv | Imod)) -> [| eax; edx |]
| Iop(Iintop_imm(Imod, _)) -> [| eax |]
| Iop(Ialloc _) -> [| eax |]
| Iop(Iintop(Icomp _) | Iintop_imm(Icomp _, _)) -> [| eax |]
| Iop(Iintoffloat) -> [| eax |]
| Iifthenelse(Ifloattest(_, _), _, _) -> [| eax |]
| _ -> [||]
let destroyed_at_raise = all_phys_regs
(* Maximal register pressure *)
let safe_register_pressure op = 4
let max_register_pressure = function
Iextcall(_, _) -> [| 4; max_int |]
| Iintop(Idiv | Imod) -> [| 5; max_int |]
| Ialloc _ | Iintop(Icomp _) | Iintop_imm(Icomp _, _) |
Iintoffloat -> [| 6; max_int |]
| _ -> [|7; max_int |]
(* Layout of the stack frame *)
let num_stack_slots = [| 0; 0 |]
let contains_calls = ref false
(* Calling the assembler *)
let assemble_file infile outfile =
Ccomp.command ("as -o " ^ outfile ^ " " ^ infile)
|
