------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- S Y S T E M . P A C K _ 5 3 -- -- -- -- B o d y -- -- -- -- -- -- 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- -- -- 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. -- -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- -- -- ------------------------------------------------------------------------------ with System.Storage_Elements; with System.Unsigned_Types; with Unchecked_Conversion; package body System.Pack_53 is subtype Ofs is System.Storage_Elements.Storage_Offset; subtype Uns is System.Unsigned_Types.Unsigned; subtype N07 is System.Unsigned_Types.Unsigned range 0 .. 7; use type System.Storage_Elements.Storage_Offset; use type System.Unsigned_Types.Unsigned; type Cluster is record E0, E1, E2, E3, E4, E5, E6, E7 : Bits_53; end record; for Cluster use record E0 at 0 range 0 * Bits .. 0 * Bits + Bits - 1; E1 at 0 range 1 * Bits .. 1 * Bits + Bits - 1; E2 at 0 range 2 * Bits .. 2 * Bits + Bits - 1; E3 at 0 range 3 * Bits .. 3 * Bits + Bits - 1; E4 at 0 range 4 * Bits .. 4 * Bits + Bits - 1; E5 at 0 range 5 * Bits .. 5 * Bits + Bits - 1; E6 at 0 range 6 * Bits .. 6 * Bits + Bits - 1; E7 at 0 range 7 * Bits .. 7 * Bits + Bits - 1; end record; for Cluster'Size use Bits * 8; for Cluster'Alignment use Integer'Min (Standard'Maximum_Alignment, 1 + 1 * Boolean'Pos (Bits mod 2 = 0) + 2 * Boolean'Pos (Bits mod 4 = 0)); -- Use maximum possible alignment, given the bit field size, since this -- will result in the most efficient code possible for the field. type Cluster_Ref is access Cluster; function To_Ref is new Unchecked_Conversion (System.Address, Cluster_Ref); ------------ -- Get_53 -- ------------ function Get_53 (Arr : System.Address; N : Natural) return Bits_53 is C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8)); begin case N07 (Uns (N) mod 8) is when 0 => return C.E0; when 1 => return C.E1; when 2 => return C.E2; when 3 => return C.E3; when 4 => return C.E4; when 5 => return C.E5; when 6 => return C.E6; when 7 => return C.E7; end case; end Get_53; ------------ -- Set_53 -- ------------ procedure Set_53 (Arr : System.Address; N : Natural; E : Bits_53) is C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8)); begin case N07 (Uns (N) mod 8) is when 0 => C.E0 := E; when 1 => C.E1 := E; when 2 => C.E2 := E; when 3 => C.E3 := E; when 4 => C.E4 := E; when 5 => C.E5 := E; when 6 => C.E6 := E; when 7 => C.E7 := E; end case; end Set_53; end System.Pack_53;