1*44028SbosticProblem: By returning p->forw, we kill the std's operand, which in turn 2*44028Sbosticcauses the std to be deleted the next time around. 3*44028SbosticWe WANT this to occur, however, if there are no more 4*44028Sbosticuses of r0 or r1 between q and the original uses[r]. 5*44028SbosticSo we must loop in flops() until we run out of uses. 6