158 lines
6.1 KiB
Ada
158 lines
6.1 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- S Y S T E M . P A C K _ 2 7 --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with System.Storage_Elements;
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with System.Unsigned_Types;
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package body System.Pack_27 is
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subtype Bit_Order is System.Bit_Order;
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Reverse_Bit_Order : constant Bit_Order :=
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Bit_Order'Val (1 - Bit_Order'Pos (System.Default_Bit_Order));
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subtype Ofs is System.Storage_Elements.Storage_Offset;
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subtype Uns is System.Unsigned_Types.Unsigned;
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subtype N07 is System.Unsigned_Types.Unsigned range 0 .. 7;
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use type System.Storage_Elements.Storage_Offset;
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use type System.Unsigned_Types.Unsigned;
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type Cluster is record
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E0, E1, E2, E3, E4, E5, E6, E7 : Bits_27;
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end record;
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for Cluster use record
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E0 at 0 range 0 * Bits .. 0 * Bits + Bits - 1;
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E1 at 0 range 1 * Bits .. 1 * Bits + Bits - 1;
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E2 at 0 range 2 * Bits .. 2 * Bits + Bits - 1;
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E3 at 0 range 3 * Bits .. 3 * Bits + Bits - 1;
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E4 at 0 range 4 * Bits .. 4 * Bits + Bits - 1;
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E5 at 0 range 5 * Bits .. 5 * Bits + Bits - 1;
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E6 at 0 range 6 * Bits .. 6 * Bits + Bits - 1;
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E7 at 0 range 7 * Bits .. 7 * Bits + Bits - 1;
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end record;
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for Cluster'Size use Bits * 8;
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for Cluster'Alignment use Integer'Min (Standard'Maximum_Alignment,
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1 +
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1 * Boolean'Pos (Bits mod 2 = 0) +
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2 * Boolean'Pos (Bits mod 4 = 0));
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-- Use maximum possible alignment, given the bit field size, since this
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-- will result in the most efficient code possible for the field.
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type Cluster_Ref is access Cluster;
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type Rev_Cluster is new Cluster
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with Bit_Order => Reverse_Bit_Order,
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Scalar_Storage_Order => Reverse_Bit_Order;
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type Rev_Cluster_Ref is access Rev_Cluster;
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------------
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-- Get_27 --
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------------
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function Get_27
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(Arr : System.Address;
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N : Natural;
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Rev_SSO : Boolean) return Bits_27
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is
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A : constant System.Address := Arr + Bits * Ofs (Uns (N) / 8);
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C : Cluster_Ref with Address => A'Address, Import;
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RC : Rev_Cluster_Ref with Address => A'Address, Import;
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begin
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if Rev_SSO then
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case N07 (Uns (N) mod 8) is
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when 0 => return RC.E0;
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when 1 => return RC.E1;
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when 2 => return RC.E2;
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when 3 => return RC.E3;
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when 4 => return RC.E4;
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when 5 => return RC.E5;
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when 6 => return RC.E6;
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when 7 => return RC.E7;
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end case;
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else
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case N07 (Uns (N) mod 8) is
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when 0 => return C.E0;
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when 1 => return C.E1;
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when 2 => return C.E2;
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when 3 => return C.E3;
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when 4 => return C.E4;
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when 5 => return C.E5;
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when 6 => return C.E6;
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when 7 => return C.E7;
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end case;
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end if;
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end Get_27;
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------------
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-- Set_27 --
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------------
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procedure Set_27
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(Arr : System.Address;
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N : Natural;
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E : Bits_27;
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Rev_SSO : Boolean)
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is
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A : constant System.Address := Arr + Bits * Ofs (Uns (N) / 8);
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C : Cluster_Ref with Address => A'Address, Import;
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RC : Rev_Cluster_Ref with Address => A'Address, Import;
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begin
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if Rev_SSO then
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case N07 (Uns (N) mod 8) is
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when 0 => RC.E0 := E;
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when 1 => RC.E1 := E;
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when 2 => RC.E2 := E;
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when 3 => RC.E3 := E;
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when 4 => RC.E4 := E;
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when 5 => RC.E5 := E;
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when 6 => RC.E6 := E;
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when 7 => RC.E7 := E;
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end case;
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else
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case N07 (Uns (N) mod 8) is
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when 0 => C.E0 := E;
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when 1 => C.E1 := E;
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when 2 => C.E2 := E;
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when 3 => C.E3 := E;
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when 4 => C.E4 := E;
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when 5 => C.E5 := E;
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when 6 => C.E6 := E;
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when 7 => C.E7 := E;
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end case;
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end if;
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end Set_27;
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end System.Pack_27;
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