File : s-secsta.ads
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-- --
-- GNAT COMPILER COMPONENTS --
-- --
5 -- S Y S T E M . S E C O N D A R Y _ S T A C K --
-- --
-- S p e c --
-- --
-- $Revision: 1.21 $
10 -- --
-- Copyright (C) 1992-1999 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- --
15 -- 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 --
20 -- 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 --
25 -- 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. --
30 -- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
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35
with System.Storage_Elements;
package System.Secondary_Stack is
40 package SSE renames System.Storage_Elements;
Default_Secondary_Stack_Size : constant := 10 * 1024;
-- Default size of a secondary stack
45 procedure SS_Init
(Stk : in out System.Address;
Size : Natural := Default_Secondary_Stack_Size);
-- Initialize the secondary stack with a main stack of the given Size.
--
50 -- If System.Parameters.Sec_Stack_Ratio equals Dynamic, Stk is really an
-- "out" parameter that will be allocated on the heap. Then all further
-- allocations which do not overflow the main stack will not generate
-- dynamic (de)allocation calls. If the main Stack overflows, a new
-- chuck of at least the same size will be allocated and linked to the
55 -- previous chunk.
--
-- Otherwise (Sec_Stack_Ratio between 0 and 100), Stk is an "in" parameter
-- that is already pointing to a Stack_Id. The secondary stack in this case
-- is fixed, and any attempt to allocated more than the initial size will
60 -- result in a Storage_Error being raised.
--
-- Note: the reason that Stk is passed is that SS_Init is called before
-- the proper interface is established to obtain the address of the
-- stack using System.Soft_Links.Get_Sec_Stack_Addr.
65
procedure SS_Allocate
(Address : out System.Address;
Storage_Size : SSE.Storage_Count);
-- Allocate enough space for a 'Storage_Size' bytes object with Maximum
70 -- alignment. The address of the allocated space is returned in 'Address'
procedure SS_Free (Stk : in out System.Address);
-- Release the memory allocated for the Secondary Stack. That is to say,
-- all the allocated chuncks.
75 -- Upon return, Stk will be set to System.Null_Address
type Mark_Id is private;
-- Type used to mark the stack.
80 function SS_Mark return Mark_Id;
-- Return the Mark corresponding to the current state of the stack
procedure SS_Release (M : Mark_Id);
-- Restore the state of the stack corresponding to the mark M. If an
85 -- additional chunk have been allocated, it will never be freed during a
generic
with procedure Put_Line (S : String);
procedure SS_Info;
90 -- Debugging procedure used to print out secondary Stack allocation
-- information. This procedure is generic in order to avoid a direct
-- dependance on a particular IO package.
private
95
SS_Pool : Integer;
-- Unused entity that is just present to ease the sharing of the pool
-- mechanism for specific allocation/deallocation in the compiler
100 type Mark_Id is new SSE.Integer_Address;
end System.Secondary_Stack;