Ending the Loop

## x' = (1/2)(x + n/x)

## $f0  ---  n
## $f1  ---  1.0
## $f2  ---  2.0
## $f3  ---  x  : current approx.
## $f4  ---  x' : next approx.
## $f8  ---  temp
## $f10 ---  small value

loop:   
        mov.s   $f4,$f0             #  x' = n
        div.s   $f4,$f4,$f3         #  x' = n/x
        add.s   $f4,$f3,$f4         #  x' = x + n/x
        div.s   $f3,$f4,$f2         #  x = (1/2)(x + n/x)

        # test if loop should end

After calculting a new approximation it is time to see if the loop should end. This is more work than the actual calculation. We can't test if we have the exact answer yet, because that may never happen. Instead let us test if the current x is close to the square root of n