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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . S E C O N D A R Y _ S T A C K --
-- --
-- B o d y --
-- --
-- --
-- Copyright (C) 1992-2001 Free Software Foundation, Inc. --
-- --
-- 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, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, 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 is the HI-E version of this package.
with Unchecked_Conversion;
package body System.Secondary_Stack is
use type SSE.Storage_Offset;
type Memory is array (Mark_Id range <>) of SSE.Storage_Element;
type Stack_Id is record
Top : Mark_Id;
Last : Mark_Id;
Mem : Memory (1 .. Mark_Id'Last);
end record;
pragma Suppress_Initialization (Stack_Id);
type Stack_Ptr is access Stack_Id;
function From_Addr is new Unchecked_Conversion (Address, Stack_Ptr);
function Get_Sec_Stack return Stack_Ptr;
pragma Import (C, Get_Sec_Stack, "__gnat_get_secondary_stack");
-- Return the address of the secondary stack.
-- In a multi-threaded environment, Sec_Stack should be a thread-local
-- variable.
-- Possible implementation of Get_Sec_Stack in a single-threaded
-- environment:
--
-- Chunk : aliased Memory (1 .. Default_Secondary_Stack_Size);
-- for Chunk'Alignment use Standard'Maximum_Alignment;
-- -- The secondary stack.
--
-- function Get_Sec_Stack return Stack_Ptr is
-- begin
-- return From_Addr (Chunk'Address);
-- end Get_Sec_Stack;
--
-- begin
-- SS_Init (Chunk'Address, Default_Secondary_Stack_Size);
-- end System.Secondary_Stack;
-----------------
-- SS_Allocate --
-----------------
procedure SS_Allocate
(Address : out System.Address;
Storage_Size : SSE.Storage_Count)
is
Max_Align : constant Mark_Id := Mark_Id (Standard'Maximum_Alignment);
Max_Size : constant Mark_Id :=
((Mark_Id (Storage_Size) + Max_Align - 1) / Max_Align)
* Max_Align;
Sec_Stack : constant Stack_Ptr := Get_Sec_Stack;
begin
if Sec_Stack.Top + Max_Size > Sec_Stack.Last then
raise Storage_Error;
end if;
Address := Sec_Stack.Mem (Sec_Stack.Top)'Address;
Sec_Stack.Top := Sec_Stack.Top + Mark_Id (Max_Size);
end SS_Allocate;
-------------
-- SS_Free --
-------------
procedure SS_Free (Stk : in out System.Address) is
begin
Stk := Null_Address;
end SS_Free;
-------------
-- SS_Init --
-------------
procedure SS_Init
(Stk : System.Address;
Size : Natural := Default_Secondary_Stack_Size)
is
Stack : Stack_Ptr := From_Addr (Stk);
begin
pragma Assert (Size >= 2 * Mark_Id'Max_Size_In_Storage_Elements);
Stack.Top := Stack.Mem'First;
Stack.Last := Mark_Id (Size) - 2 * Mark_Id'Max_Size_In_Storage_Elements;
end SS_Init;
-------------
-- SS_Mark --
-------------
function SS_Mark return Mark_Id is
begin
return Get_Sec_Stack.Top;
end SS_Mark;
----------------
-- SS_Release --
----------------
procedure SS_Release (M : Mark_Id) is
begin
Get_Sec_Stack.Top := M;
end SS_Release;
end System.Secondary_Stack;
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