126 lines
5.5 KiB
Ada
126 lines
5.5 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . V E C T O R S . B O O L E A N _ O P E R A T I O N S --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 2002-2009, 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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package body System.Vectors.Boolean_Operations is
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SU : constant := Storage_Unit;
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-- Convenient short hand, used throughout
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-- The coding of this unit depends on the fact that the Component_Size
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-- of a normally declared array of Boolean is equal to Storage_Unit. We
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-- can't use the Component_Size directly since it is non-static. The
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-- following declaration checks that this declaration is correct
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type Boolean_Array is array (Integer range <>) of Boolean;
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pragma Compile_Time_Error
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(Boolean_Array'Component_Size /= SU, "run time compile failure");
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-- NOTE: The boolean literals must be qualified here to avoid visibility
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-- anomalies when this package is compiled through Rtsfind, in a context
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-- that includes a user-defined type derived from boolean.
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True_Val : constant Vector := Standard.True'Enum_Rep
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+ Standard.True'Enum_Rep * 2**SU
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+ Standard.True'Enum_Rep * 2**(SU * 2)
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+ Standard.True'Enum_Rep * 2**(SU * 3)
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+ Standard.True'Enum_Rep * 2**(SU * 4)
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+ Standard.True'Enum_Rep * 2**(SU * 5)
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+ Standard.True'Enum_Rep * 2**(SU * 6)
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+ Standard.True'Enum_Rep * 2**(SU * 7);
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-- This constant represents the bits to be flipped to perform a logical
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-- "not" on a vector of booleans, independent of the actual
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-- representation of True.
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-- The representations of (False, True) are assumed to be zero/one and
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-- the maximum number of unpacked booleans per Vector is assumed to be 8.
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pragma Assert (Standard.False'Enum_Rep = 0);
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pragma Assert (Standard.True'Enum_Rep = 1);
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pragma Assert (Vector'Size / Storage_Unit <= 8);
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-- The reason we need to do these gymnastics is that no call to
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-- Unchecked_Conversion can be made at the library level since this
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-- unit is pure. Also a conversion from the array type to the Vector type
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-- inside the body of "not" is inefficient because of alignment issues.
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-----------
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-- "not" --
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-----------
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function "not" (Item : Vectors.Vector) return Vectors.Vector is
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begin
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return Item xor True_Val;
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end "not";
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----------
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-- Nand --
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----------
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function Nand (Left, Right : Boolean) return Boolean is
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begin
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return not (Left and Right);
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end Nand;
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function Nand (Left, Right : Vectors.Vector) return Vectors.Vector is
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begin
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return not (Left and Right);
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end Nand;
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---------
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-- Nor --
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---------
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function Nor (Left, Right : Boolean) return Boolean is
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begin
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return not (Left or Right);
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end Nor;
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function Nor (Left, Right : Vectors.Vector) return Vectors.Vector is
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begin
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return not (Left or Right);
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end Nor;
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----------
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-- Nxor --
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----------
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function Nxor (Left, Right : Boolean) return Boolean is
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begin
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return not (Left xor Right);
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end Nxor;
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function Nxor (Left, Right : Vectors.Vector) return Vectors.Vector is
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begin
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return not (Left xor Right);
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end Nxor;
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end System.Vectors.Boolean_Operations;
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