matlab chi square code with errors in x and y giving gradient

Does anyone know of a fitchisquare code that allows you to give the gradient and intercept of the fit, give values of x dx y dy and get an estimate of chi squared value out?

I have a code at the moment which gives me the reduced chi squared and outputs the gradient and intercept. To perform an F test I want to see what the chi squared is for a gradient=0.

Any ideas?