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1 ## Copyright (C) 2004 David BAteman |
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2 ## |
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3 ## This program is free software; you can redistribute it and/or modify |
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4 ## it under the terms of the GNU General Public License as published by |
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5 ## the Free Software Foundation; either version 2 of the License, or |
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6 ## (at your option) any later version. |
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7 ## |
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8 ## This program is distributed in the hope that it will be useful, |
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9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of |
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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11 ## GNU General Public License for more details. |
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12 ## |
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13 ## You should have received a copy of the GNU General Public License |
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14 ## along with this program; if not, write to the Free Software |
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15 ## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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16 |
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17 ## -*- texinfo -*- |
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18 ## @deftypefn {Function File} {@var{X} =} bitget (@var{a},@var{n}) |
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19 ## returns the status of bit(s) @var{n} of unsigned integers in @var{a} |
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20 ## the lowest significant bit is @var{n} = 1. |
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21 ## |
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22 ## @example |
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23 ## bitget(100,8:-1:1) |
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24 ## @result{} 0 1 1 0 0 1 0 0 |
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25 ## @end example |
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26 ## @seealso{bitand,bitor,bitxor,bitset,bitcmp,bitshift,bitmax} |
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27 ## @end deftypefn |
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28 |
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29 ## Liberally based of the version by Kai Habel from octave-forge |
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30 |
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31 function X = bitget (A, n) |
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32 if (nargin != 2) |
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33 usage ("bitget(A,n)"); |
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34 endif |
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35 |
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36 cname = class(A); |
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37 if (strcmp (cname, "double")) |
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38 Amax = log2 (bitmax) + 1; |
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39 elseif strcmp("uint",substr(cname,1,4)) |
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40 Amax = eval([cname, " (log2 (double (intmax (cname))) + 1);"]); |
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41 else |
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42 Amax = eval([cname, " (log2 (double (intmax (cname))) + 2);"]); |
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43 endif |
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44 |
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45 Aone = eval([ cname, "(1);"]); |
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46 m = eval([cname, " (n(:));"]); |
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47 if (any(m < Aone) || any( m > Amax)) |
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48 error ("n must be in the range [1,%d]", Amax); |
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49 endif |
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50 |
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51 X = eval (["bitand (A, ", cname, " (2) .^ (", cname, " (n) - Aone)) != ", cname, "(0);"]); |
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52 |
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53 endfunction |
