How do I get real integer overflows in MATLAB/Octave?

Question

I\'m working on a verification-tool for some VHDL-Code in MATLAB/Octave. Therefore I need data types which generate \"real\" overflows:

intmax(\'int32\') + 1         


        

Answer 1

Hm, yes...

Actually, I was able to solve the problem with my custom "overflow"-Subroutine... Now it runs painfully slow, but without unexpected behaviour! My mistake was a missing round(), since Matlab/Octave will introduce small errors.

But if someone knows a faster solution, I would be glad to try it!

function ret = overflow_sg(arg,bw)

    % remove possible rounding errors, and prepare returnvalue (if number is inside boundaries, nothing will happen)
    ret = round(arg);

    argsize = size(ret);

    for i = 1:argsize(1)
        for j = 1:argsize(2)
            ret(i,j) = flow_sg(ret(i,j),bw);
        end
    end

end%function

%---

function ret = flow_sg(arg,bw)
    ret = arg;
    while (ret < (-2^(bw-1)))
        ret = ret + 2^bw;
    end

    % Check for overflows:
    while (ret > (2^(bw-1)-1))
        ret = ret - 2^bw;
    end
end%function