------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . M E M O R Y _ T Y P E S --
-- --
-- S p e c --
-- --
-- Copyright (C) 2017-2023, 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 3, 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Unchecked_Conversion;
package System.Memory_Types is
pragma No_Elaboration_Code_All;
pragma Preelaborate;
type size_t is mod 2 ** Standard'Address_Size;
-- The type corresponding to size_t in C. We cannot reuse the one defined
-- in Interfaces.C as we want this package not to have any elaboration
-- code.
type IA is mod System.Memory_Size;
-- The type used to provide the actual desired operations
function To_IA is new Ada.Unchecked_Conversion (Address, IA);
-- The operations are implemented by unchecked conversion to type IA,
-- followed by doing the intrinsic operation on the IA values, followed
-- by converting the result back to type Address.
type Byte is mod 2 ** 8;
for Byte'Size use 8;
-- Byte is the storage unit
type Byte_Ptr is access Byte;
-- Access to a byte
function To_Byte_Ptr is new Ada.Unchecked_Conversion (IA, Byte_Ptr);
-- Conversion between an integer address and access to byte
Byte_Unit : constant := 1;
-- Number of storage unit in a byte
type Word is mod 2 ** System.Word_Size;
for Word'Size use System.Word_Size;
-- Word is efficiently loaded and stored by the processor, but has
-- alignment constraints.
type Word_Ptr is access Word;
-- Access to a word.
function To_Word_Ptr is new Ada.Unchecked_Conversion (IA, Word_Ptr);
-- Conversion from an integer address to word access
Word_Unit : constant := Word'Size / Storage_Unit;
-- Number of storage unit per word
end System.Memory_Types;