vb_bitand_ex

 An enhanced version of 'logical AND' function 'bitand'.
 The new one can accept negative number.
 [usage]
   result = vb_bitand_ex(num1, num2, bit_len)
 [input]
      num1 : number #1 [1 x N]
      num2 : number #2 [1 x N] or [x1]
   bit_len : length of bit
 [output]
    result : result of logical AND (base-10)
 [note]
   convert negative to positive and use 'bitand'
 [history]
   2007-01-09 (Sako) initial version

 Copyright (C) 2011, ATR All Rights Reserved.
 License : New BSD License(see VBMEG_LICENSE.txt)

0001 function result = vb_bitand_ex(num1, num2, bit_len)
0002 % An enhanced version of 'logical AND' function 'bitand'.
0003 % The new one can accept negative number.
0004 % [usage]
0005 %   result = vb_bitand_ex(num1, num2, bit_len)
0006 % [input]
0007 %      num1 : number #1 [1 x N]
0008 %      num2 : number #2 [1 x N] or [x1]
0009 %   bit_len : length of bit
0010 % [output]
0011 %    result : result of logical AND (base-10)
0012 % [note]
0013 %   convert negative to positive and use 'bitand'
0014 % [history]
0015 %   2007-01-09 (Sako) initial version
0016 %
0017 % Copyright (C) 2011, ATR All Rights Reserved.
0018 % License : New BSD License(see VBMEG_LICENSE.txt)
0019 
0020 if any(num1 < 0)
0021   num1 = inner_convert_negative2positive(num1, bit_len);
0022 end
0023 
0024 if any(num2 < 0)
0025   num2 = inner_convert_negative2positive(num2, bit_len);
0026 end
0027 
0028 result = bitand(num1,num2);
0029 
0030 % --- INNER FUNCTIONS -------------------------------------------------------- %
0031 %
0032 % --- inner_convert_negative2positive()
0033 %
0034 function p_num = inner_convert_negative2positive(n_num, bit_len)
0035 
0036 len_num = length(n_num);
0037 p_num = zeros(1,len_num);
0038 for i_num = 1:len_num
0039   if n_num(i_num) >= 0
0040     p_num(i_num) = n_num(i_num);
0041   else
0042     p_num(i_num) = n_num(i_num) + 2^bit_len;
0043   end
0044 end
0045 
0046 % p_num = n_num + 2^bit_len;
0047 %
0048 % --- end of inner_convert_negative2positive()
0049 
0050 %%% END OF FILE %%%