Mercurial > octave
view scripts/general/bitcmp.m @ 31246:43a6be589387
doc: New documentation for memoization techniques (bug #60860)
vectorize.texi: New section on memoization
octave.texi: List new section
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Thu, 29 Sep 2022 20:31:52 -0400 |
parents | 5d3faba0342e |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2004-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## This file is part of Octave. ## ## Octave is free software: you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation, either version 3 of the License, or ## (at your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT 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 ## along with Octave; see the file COPYING. If not, see ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{C} =} bitcmp (@var{A}, @var{k}) ## Return the @var{k}-bit complement of integers in @var{A}. ## ## If @var{k} is omitted @code{k = log2 (flintmax) + 1} is assumed. ## ## @example ## @group ## bitcmp (7,4) ## @result{} 8 ## dec2bin (11) ## @result{} 1011 ## dec2bin (bitcmp (11, 6)) ## @result{} 110100 ## @end group ## @end example ## ## @seealso{bitand, bitor, bitxor, bitset, bitget, bitcmp, bitshift, flintmax} ## @end deftypefn ## Liberally based on the version by Kai Habel from Octave Forge function C = bitcmp (A, k) if (nargin < 1) print_usage (); endif if (nargin == 2 && (! isscalar (k) || (floor (k) != k))) error ("bitcmp: K must be a scalar integer"); endif if (isa (A, "double")) bmax = flintmax - 1; amax = ceil (log2 (bmax)); elseif (isa (A, "single")) bmax = flintmax ("single") - 1; amax = ceil (log2 (bmax)); elseif (isinteger (A)) amax = sizeof (ones (1, class (A))) * 8; bmax = bitpack (true (amax, 1), class (A)); else error ("bitcmp: invalid class %s", class (A)); endif if (nargin == 1 || k == amax) C = bitxor (A, bmax); else m = double (k); if (any (m < 1) || any (m > amax)) error ("bitcmp: K must be in the range [1,%d]", amax); endif mask = bitshift (bmax, k - amax); C = bitxor (bitand (A, mask), mask); endif endfunction %!test %! Amax = 53; %! Bmax = flintmax - 1; %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax),bitor (bitshift (1,Amax-1), bitshift (1,Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (1,Amax-2)); %! assert (bitcmp (A,Amax-2), 0); %!test %! Amax = 24; %! Bmax = flintmax ("single") - 1; %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax), %! bitor (bitshift (single (1),Amax-1), bitshift (single (1),Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (single (1),Amax-2)); %! assert (bitcmp (A,Amax-2), single (0)); %!test %! Amax = 8; %! Bmax = intmax ("uint8"); %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax), %! bitor (bitshift (uint8 (1),Amax-1), bitshift (uint8 (1),Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (uint8 (1),Amax-2)); %! assert (bitcmp (A,Amax-2), uint8 (0)); %!test %! Amax = 16; %! Bmax = intmax ("uint16"); %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax), %! bitor (bitshift (uint16 (1),Amax-1), bitshift (uint16 (1),Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (uint16 (1),Amax-2)); %! assert (bitcmp (A,Amax-2), uint16 (0)); %!test %! Amax = 32; %! Bmax = intmax ("uint32"); %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax), %! bitor (bitshift (uint32 (1),Amax-1), bitshift (uint32 (1),Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (uint32 (1),Amax-2)); %! assert (bitcmp (A,Amax-2), uint32 (0)); %!test %! Amax = 64; %! Bmax = intmax ("uint64"); %! A = bitshift (Bmax,-2); %! assert (bitcmp (A,Amax), %! bitor (bitshift (uint64 (1),Amax-1), bitshift (uint64 (1),Amax-2))); %! assert (bitcmp (A,Amax-1), bitshift (uint64 (1),Amax-2)); %! assert (bitcmp (A,Amax-2), uint64 (0)); ## Do not forget signed integers %!assert (bitcmp (int8 (127)), int8 (-128)) # [1 1 1 1 1 1 1 0] %!assert (bitcmp (int8 (1)), int8 (-2)) # [1 0 0 0 0 0 0 0] %!assert (bitcmp (int8 (0)), int8 (-1)) # [0 0 0 0 0 0 0 0] %!assert (bitcmp (int8 (8)), int8 (-9)) # [0 0 0 1 0 0 0 0]