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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- SYSTEM.MACHINE_STATE_OPERATIONS --
-- --
-- B o d y --
-- (Version for Alpha/Dec Unix) --
-- --
-- Copyright (C) 1999-2005, 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 DEC Unix.
with System.Memory;
package body System.Machine_State_Operations is
pragma Linker_Options ("-lexc");
-- Needed for definitions of exc_capture_context and exc_virtual_unwind
----------------------------
-- Allocate_Machine_State --
----------------------------
function Allocate_Machine_State return Machine_State is
use System.Storage_Elements;
function c_machine_state_length return Storage_Offset;
pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
begin
return Machine_State
(Memory.Alloc (Memory.size_t (c_machine_state_length)));
end Allocate_Machine_State;
----------------
-- Fetch_Code --
----------------
function Fetch_Code (Loc : Code_Loc) return Code_Loc is
begin
return Loc;
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
Asm_Call_Size : constant := 4;
function c_get_code_loc (M : Machine_State) return Code_Loc;
pragma Import (C, c_get_code_loc, "__gnat_get_code_loc");
-- Code_Loc returned by c_get_code_loc is the return point but here we
-- want Get_Code_Loc to return the call point. Under DEC Unix a call
-- asm instruction takes 4 bytes. So we must remove this value from
-- c_get_code_loc to have the call point.
Loc : constant Code_Loc := c_get_code_loc (M);
begin
if Loc = 0 then
return 0;
else
return Loc - Asm_Call_Size;
end if;
end Get_Code_Loc;
--------------------------
-- Machine_State_Length --
--------------------------
function Machine_State_Length
return System.Storage_Elements.Storage_Offset
is
use System.Storage_Elements;
function c_machine_state_length return Storage_Offset;
pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
begin
return c_machine_state_length;
end Machine_State_Length;
---------------
-- Pop_Frame --
---------------
procedure Pop_Frame (M : Machine_State) is
procedure exc_virtual_unwind (Fcn : System.Address; M : Machine_State);
pragma Import (C, exc_virtual_unwind, "exc_virtual_unwind");
function exc_lookup_function (Loc : Code_Loc) return System.Address;
pragma Import (C, exc_lookup_function, "exc_lookup_function_entry");
procedure c_set_code_loc (M : Machine_State; Loc : Code_Loc);
pragma Import (C, c_set_code_loc, "__gnat_set_code_loc");
-- Look for a code-range descriptor table containing the PC of the
-- specified machine state. If we don't find any, attempting to unwind
-- further would fail so we set the machine state's code location to a
-- value indicating that the top of the call chain is reached. This
-- happens when the function at the address pointed to by PC has not
-- been registered with the unwinding machinery, as with the __istart
-- functions generated by the linker in presence of initialization
-- routines for example.
Prf : constant System.Address := exc_lookup_function (Get_Code_Loc (M));
begin
if Prf = System.Null_Address then
c_set_code_loc (M, 0);
else
exc_virtual_unwind (Prf, M);
end if;
end Pop_Frame;
-----------------------
-- Set_Machine_State --
-----------------------
procedure Set_Machine_State (M : Machine_State) is
procedure c_capture_context (M : Machine_State);
pragma Import (C, c_capture_context, "exc_capture_context");
begin
c_capture_context (M);
Pop_Frame (M);
end Set_Machine_State;
end System.Machine_State_Operations;
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