File : s-veboop.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
4 -- --
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 --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 2002-2009, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This package contains functions for runtime operations on boolean vectors
33
34 package System.Vectors.Boolean_Operations is
35 pragma Pure;
36
37 -- Although in general the boolean operations on arrays of booleans are
38 -- identical to operations on arrays of unsigned words of the same size,
39 -- for the "not" operator this is not the case as False is typically
40 -- represented by 0 and true by 1.
41
42 function "not" (Item : Vectors.Vector) return Vectors.Vector;
43
44 -- The three boolean operations "nand", "nor" and "nxor" are needed
45 -- for cases where the compiler moves boolean array operations into
46 -- the body of the loop that iterates over the array elements.
47
48 -- Note the following equivalences:
49 -- (not X) or (not Y) = not (X and Y) = Nand (X, Y)
50 -- (not X) and (not Y) = not (X or Y) = Nor (X, Y)
51 -- (not X) xor (not Y) = X xor Y
52 -- X xor (not Y) = not (X xor Y) = Nxor (X, Y)
53
54 function Nand (Left, Right : Boolean) return Boolean;
55 function Nor (Left, Right : Boolean) return Boolean;
56 function Nxor (Left, Right : Boolean) return Boolean;
57
58 function Nand (Left, Right : Vectors.Vector) return Vectors.Vector;
59 function Nor (Left, Right : Vectors.Vector) return Vectors.Vector;
60 function Nxor (Left, Right : Vectors.Vector) return Vectors.Vector;
61
62 pragma Inline_Always ("not");
63 pragma Inline_Always (Nand);
64 pragma Inline_Always (Nor);
65 pragma Inline_Always (Nxor);
66 end System.Vectors.Boolean_Operations;