Mercurial > hg > octave-lyh
view scripts/general/bitset.m @ 4918:d2a7208f35d4
[project @ 2004-07-27 15:18:04 by jwe]
author | jwe |
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date | Tue, 27 Jul 2004 15:18:04 +0000 |
parents | c45f14873b5e |
children | b22a7a1db0d5 |
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## Copyright (C) 2004 David BAteman ## ## This program 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 2 of the License, or ## (at your option) any later version. ## ## This program 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 this program; if not, write to the Free Software ## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ## -*- texinfo -*- ## @deftypefn {Function File} {@var{X} =} bitset (@var{a},@var{n}) ## @deftypefnx {Function File} {@var{X} =} bitset (@var{a},@var{n},@var{v}) ## sets or resets bit(s) @var{N} of unsigned integers in @var{A}. ## @var{v} = 0 resets and @var{v} = 1 sets the bits. ## The lowest significant bit is: @var{n} = 1 ## ## @example ## dec2bin (bitset(10,1)) ## @result{} 1011 ## @end example ## ## @seealso{bitand,bitor,bitxor,bitget,bitcmp,bitshift,bitmax} ## @end deftypefn ## Liberally based of the version by Kai Habel from octave-forge function X = bitset (A, n, value) if (nargin < 2 || nargin > 3) usage ("bitset (A, n, v)"); endif if (nargin == 2) value = 1; endif cname = class(A); if (strcmp (cname, "double")) Bmax = bitmax; Amax = log2 (Bmax) + 1; elseif strcmp("uint",substr(cname,1,4)) Bmax = intmax(cname); Amax = eval([cname, " (log2 (double (intmax (cname))) + 1);"]); else Bmax = eval([cname, " (-1);"]); Amax = eval([cname, " (log2 (double (intmax (cname))) + 2);"]); endif Aone = eval([ cname, "(1);"]); m = eval([cname, " (n(:));"]); if (any(m < Aone) || any( m > Amax)) error ("n must be in the range [1,%d]", Amax); endif ## XXX FIXME XXX Need extra cast to cname due to bad return value of .^ X = eval (["bitand (A, Bmax - ", cname, " (", cname, " (2) .^ (", cname, " (n) - Aone)));"]); if (value) X = eval (["bitor (A, ", cname, " (2) .^ (", cname, " (n) - Aone));"]); endif endfunction