| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 1992-2004 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 + 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; |
