Two's Complement for MATLAB

Calculating two's complement for a decimal number.

Description

Calculate two's complement for a signed integer in MATLAB.

• Acknowledgements: This submission has inspired the following:; Two's Complement
• MATLAB release: MATLAB 6.5 (R13)

[Shyang-Wen Tseng]

It is fascinating to read the author's wit of how to program to get the two's complement of an integer number. It is very useful not only in its usage but also its wit of programing it. Thank you.

[igi donegor]

 

[Chad Webb]

Handy for 16 bit numbers, but not anything else. It even takes an input for what appears to be the number of bits (i.e. other than 16), but never utilizes it. Good start on a function that could be far more useful.

[Rafael Baur]

there is a easier way to calculate the two's complement:
twos_comp = dec2bin(mod((value),2^bits),bits);

look at a those two's complement circles then you will see why it works.

[Hassan Naseri]

function value = dec2tc(dec, N)
value = dec2bin(mod((dec),2^N),N);
end

function value = tc2dec(bin,N)
val = bin2dec(bin);
y = sign(2^(N-1)-val)*(2^(N-1)-abs(2^(N-1)-val));
if ((y == 0) && (val ~= 0))
  value = -val;
else
    value = y;
end
end

[duanra]

 if N is the number of bit
and b an array of integer to convert in signed this operation could be faster

       if( b(n) > (2^(N-1)-1))
            b(n)=b(n)-2^N;
        else
            b(n)=b(n);
        end;