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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- SYSTEM.MACHINE_STATE_OPERATIONS --
-- --
-- B o d y --
-- (Version for Alpha/VMS) --
-- --
-- Copyright (C) 2001-2005, AdaCore --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This version of System.Machine_State_Operations is for use on
-- Alpha systems running VMS.
with System.Memory;
with System.Aux_DEC; use System.Aux_DEC;
with Unchecked_Conversion;
package body System.Machine_State_Operations is
subtype Cond_Value_Type is Unsigned_Longword;
-- Record layouts copied from Starlet
type ICB_Fflags_Bits_Type is record
Exception_Frame : Boolean;
Ast_Frame : Boolean;
Bottom_Of_Stack : Boolean;
Base_Frame : Boolean;
Filler_1 : Unsigned_20;
end record;
for ICB_Fflags_Bits_Type use record
Exception_Frame at 0 range 0 .. 0;
Ast_Frame at 0 range 1 .. 1;
Bottom_Of_Stack at 0 range 2 .. 2;
Base_Frame at 0 range 3 .. 3;
Filler_1 at 0 range 4 .. 23;
end record;
for ICB_Fflags_Bits_Type'Size use 24;
type ICB_Hdr_Quad_Type is record
Context_Length : Unsigned_Longword;
Fflags_Bits : ICB_Fflags_Bits_Type;
Block_Version : Unsigned_Byte;
end record;
for ICB_Hdr_Quad_Type use record
Context_Length at 0 range 0 .. 31;
Fflags_Bits at 4 range 0 .. 23;
Block_Version at 7 range 0 .. 7;
end record;
for ICB_Hdr_Quad_Type'Size use 64;
type Invo_Context_Blk_Type is record
Hdr_Quad : ICB_Hdr_Quad_Type;
-- The first quadword contains:
-- o The length of the structure in bytes (a longword field)
-- o The frame flags (a 3 byte field of bits)
-- o The version number (a 1 byte field)
Procedure_Descriptor : Unsigned_Quadword;
-- The address of the procedure descriptor for the procedure
Program_Counter : Integer_64;
-- The current PC of a given procedure invocation
Processor_Status : Integer_64;
-- The current PS of a given procedure invocation
Ireg : Unsigned_Quadword_Array (0 .. 30);
Freg : Unsigned_Quadword_Array (0 .. 30);
-- The register contents areas. 31 for scalars, 31 for float
System_Defined : Unsigned_Quadword_Array (0 .. 1);
-- The following is an "internal" area that's reserved for use by
-- the operating system. It's size may vary over time.
-- Chfctx_Addr : Unsigned_Quadword;
-- Defined as a comment since it overlaps other fields
Filler_1 : String (1 .. 0);
-- Align to octaword
end record;
for Invo_Context_Blk_Type use record
Hdr_Quad at 0 range 0 .. 63;
Procedure_Descriptor at 8 range 0 .. 63;
Program_Counter at 16 range 0 .. 63;
Processor_Status at 24 range 0 .. 63;
Ireg at 32 range 0 .. 1983;
Freg at 280 range 0 .. 1983;
System_Defined at 528 range 0 .. 127;
-- Component representation spec(s) below are defined as
-- comments since they overlap other fields
-- Chfctx_Addr at 528 range 0 .. 63;
Filler_1 at 544 range 0 .. -1;
end record;
for Invo_Context_Blk_Type'Size use 4352;
subtype Invo_Handle_Type is Unsigned_Longword;
type Invo_Handle_Access_Type is access all Invo_Handle_Type;
function Fetch is new Fetch_From_Address (Code_Loc);
function To_Invo_Handle_Access is new Unchecked_Conversion
(Machine_State, Invo_Handle_Access_Type);
function To_Machine_State is new Unchecked_Conversion
(System.Address, Machine_State);
----------------------------
-- Allocate_Machine_State --
----------------------------
function Allocate_Machine_State return Machine_State is
begin
return To_Machine_State
(Memory.Alloc (Invo_Handle_Type'Max_Size_In_Storage_Elements));
end Allocate_Machine_State;
----------------
-- Fetch_Code --
----------------
function Fetch_Code (Loc : Code_Loc) return Code_Loc is
begin
-- The starting address is in the second longword pointed to by Loc
return Fetch (System.Aux_DEC."+" (Loc, 8));
end Fetch_Code;
------------------------
-- Free_Machine_State --
------------------------
procedure Free_Machine_State (M : in out Machine_State) is
begin
Memory.Free (Address (M));
M := Machine_State (Null_Address);
end Free_Machine_State;
------------------
-- Get_Code_Loc --
------------------
function Get_Code_Loc (M : Machine_State) return Code_Loc is
procedure Get_Invo_Context (
Result : out Unsigned_Longword; -- return value
Invo_Handle : in Invo_Handle_Type;
Invo_Context : out Invo_Context_Blk_Type);
pragma Interface (External, Get_Invo_Context);
pragma Import_Valued_Procedure (Get_Invo_Context, "LIB$GET_INVO_CONTEXT",
(Unsigned_Longword, Invo_Handle_Type, Invo_Context_Blk_Type),
(Value, Value, Reference));
Asm_Call_Size : constant := 4;
-- Under VMS a call
-- asm instruction takes 4 bytes. So we must remove this amount.
ICB : Invo_Context_Blk_Type;
Status : Cond_Value_Type;
begin
Get_Invo_Context (Status, To_Invo_Handle_Access (M).all, ICB);
if (Status and 1) /= 1 then
return Code_Loc (System.Null_Address);
end if;
return Code_Loc (ICB.Program_Counter - Asm_Call_Size);
end Get_Code_Loc;
--------------------------
-- Machine_State_Length --
--------------------------
function Machine_State_Length
return System.Storage_Elements.Storage_Offset
is
use System.Storage_Elements;
begin
return Invo_Handle_Type'Size / 8;
end Machine_State_Length;
---------------
-- Pop_Frame --
---------------
procedure Pop_Frame (M : Machine_State) is
procedure Get_Prev_Invo_Handle (
Result : out Invo_Handle_Type; -- return value
ICB : in Invo_Handle_Type);
pragma Interface (External, Get_Prev_Invo_Handle);
pragma Import_Valued_Procedure
(Get_Prev_Invo_Handle, "LIB$GET_PREV_INVO_HANDLE",
(Invo_Handle_Type, Invo_Handle_Type),
(Value, Value));
Prev_Handle : aliased Invo_Handle_Type;
begin
Get_Prev_Invo_Handle (Prev_Handle, To_Invo_Handle_Access (M).all);
To_Invo_Handle_Access (M).all := Prev_Handle;
end Pop_Frame;
-----------------------
-- Set_Machine_State --
-----------------------
procedure Set_Machine_State (M : Machine_State) is
procedure Get_Curr_Invo_Context
(Invo_Context : out Invo_Context_Blk_Type);
pragma Interface (External, Get_Curr_Invo_Context);
pragma Import_Valued_Procedure
(Get_Curr_Invo_Context, "LIB$GET_CURR_INVO_CONTEXT",
(Invo_Context_Blk_Type),
(Reference));
procedure Get_Invo_Handle (
Result : out Invo_Handle_Type; -- return value
Invo_Context : in Invo_Context_Blk_Type);
pragma Interface (External, Get_Invo_Handle);
pragma Import_Valued_Procedure (Get_Invo_Handle, "LIB$GET_INVO_HANDLE",
(Invo_Handle_Type, Invo_Context_Blk_Type),
(Value, Reference));
ICB : Invo_Context_Blk_Type;
Invo_Handle : aliased Invo_Handle_Type;
begin
Get_Curr_Invo_Context (ICB);
Get_Invo_Handle (Invo_Handle, ICB);
To_Invo_Handle_Access (M).all := Invo_Handle;
Pop_Frame (M, System.Null_Address);
end Set_Machine_State;
end System.Machine_State_Operations;
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