------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . M E M O R Y _ C O P Y -- -- -- -- B o d y -- -- -- -- Copyright (C) 2006-2014, 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. -- -- -- -- -- -- -- -- -- -- -- -- 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 -- -- . -- -- -- -- 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; with Interfaces.C; use Interfaces.C; package body System.Memory_Copy is 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_Size : 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 adddress to word access Word_Size : constant := Word'Size / Storage_Unit; -- Number of storage unit per word ------------ -- memcpy -- ------------ function memcpy (Dest : Address; Src : Address; N : size_t) return Address is D : IA := To_IA (Dest); S : IA := To_IA (Src); C : size_t := N; begin -- Try to copy per word, if alignment constraints are respected if ((D or S) and (Word'Alignment - 1)) = 0 then while C >= Word_Size loop To_Word_Ptr (D).all := To_Word_Ptr (S).all; D := D + Word_Size; S := S + Word_Size; C := C - Word_Size; end loop; end if; -- Copy the remaining byte per byte while C > 0 loop To_Byte_Ptr (D).all := To_Byte_Ptr (S).all; D := D + Byte_Size; S := S + Byte_Size; C := C - Byte_Size; end loop; return Dest; end memcpy; end System.Memory_Copy;