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|
(***********************************************************************)
(* *)
(* OCaml *)
(* *)
(* 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. *)
(* *)
(***********************************************************************)
(* Description of the Intel 386 processor *)
open Misc
open Arch
open Cmm
open Reg
open Mach
(* Which asm conventions to use *)
let masm =
match Config.ccomp_type with
| "msvc" -> true
| _ -> false
(* 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 =
if masm then
[| "eax"; "ebx"; "ecx"; "edx"; "esi"; "edi"; "ebp" |]
else
[| "%eax"; "%ebx"; "%ecx"; "%edx"; "%esi"; "%edi"; "%ebp" |]
let float_reg_name =
if masm then
[| "tos" |]
else
[| "%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 *)
(* To supplement the processor's meagre supply of registers, we also
use some global memory locations to pass arguments beyond the 6th.
These globals are denoted by Incoming and Outgoing stack locations
with negative offsets, starting at -64.
Unlike arguments passed on stack, arguments passed in globals
do not prevent tail-call elimination. The caller stores arguments
in these globals immediately before the call, and the first thing the
callee does is copy them to registers or stack locations.
Neither GC nor thread context switches can occur between these two
times. *)
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 (-64) 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 (max 0 !ofs) stack_alignment)
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(Ialloc _ | Iintop Imulh) -> [| 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 |]
(* Pure operations (without any side effect besides updating their result
registers). Note that floating-point operations are not pure
because they update the float stack. *)
let op_is_pure = function
| Icall_ind | Icall_imm _ | Itailcall_ind | Itailcall_imm _
| Iextcall _ | Istackoffset _ | Istore _ | Ialloc _
| Iintop(Icheckbound) | Iintop_imm(Icheckbound, _) -> false
| Iconst_float _ | Inegf | Iabsf | Iaddf | Isubf | Imulf | Idivf
| Iintoffloat | Ifloatofint | Iload((Single | Double | Double_u), _) -> false
| Ispecific(Ilea _) -> true
| Ispecific _ -> false
| _ -> true
(* Layout of the stack frame *)
let num_stack_slots = [| 0; 0 |]
let contains_calls = ref false
(* Calling the assembler *)
let assemble_file infile outfile =
if masm then
Ccomp.command (Config.asm ^
Filename.quote outfile ^ " " ^ Filename.quote infile ^
(if !Clflags.verbose then "" else ">NUL"))
else
Ccomp.command (Config.asm ^ " -o " ^
Filename.quote outfile ^ " " ^ Filename.quote infile)
let init () = ()
|
