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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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4 -- --
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5 -- 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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6 -- --
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7 -- S p e c --
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8 -- --
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131
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9 -- Copyright (C) 2002-2018, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 -- This package contains functions for runtime operations on boolean vectors
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33
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34 package System.Vectors.Boolean_Operations is
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35 pragma Pure;
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36
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37 -- Although in general the boolean operations on arrays of booleans are
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38 -- identical to operations on arrays of unsigned words of the same size,
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39 -- for the "not" operator this is not the case as False is typically
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40 -- represented by 0 and true by 1.
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41
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42 function "not" (Item : Vectors.Vector) return Vectors.Vector;
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43
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44 -- The three boolean operations "nand", "nor" and "nxor" are needed
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45 -- for cases where the compiler moves boolean array operations into
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46 -- the body of the loop that iterates over the array elements.
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47
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48 -- Note the following equivalences:
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49 -- (not X) or (not Y) = not (X and Y) = Nand (X, Y)
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50 -- (not X) and (not Y) = not (X or Y) = Nor (X, Y)
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51 -- (not X) xor (not Y) = X xor Y
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52 -- X xor (not Y) = not (X xor Y) = Nxor (X, Y)
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53
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54 function Nand (Left, Right : Boolean) return Boolean;
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55 function Nor (Left, Right : Boolean) return Boolean;
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56 function Nxor (Left, Right : Boolean) return Boolean;
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57
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58 function Nand (Left, Right : Vectors.Vector) return Vectors.Vector;
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59 function Nor (Left, Right : Vectors.Vector) return Vectors.Vector;
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60 function Nxor (Left, Right : Vectors.Vector) return Vectors.Vector;
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61
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62 pragma Inline_Always ("not");
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63 pragma Inline_Always (Nand);
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64 pragma Inline_Always (Nor);
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65 pragma Inline_Always (Nxor);
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66 end System.Vectors.Boolean_Operations;
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