changes the end // condition to [v = 0] rather than [u = 0]. This saves an extra // subtraction due to which coefficients were negated. // 5. Rename x and y to a and n, to capture that one is a modulus. // 6. Rearrange steps 4 through 6 slightly. Merge the loops in steps 4 and // 5 into the main loop (step 7's goto), and move step 6 to the start of // the loop iteration, ensuring each loop iteration halves at least one // value. // // Note this algorithm does not handle either input being zero. if...