;yours might be
       JNB P2.0,nxtr1  ;2 cycles
       DJNZ r0, nxtr1  ;2 cycles
       CLR P2.0        ;1 cycle
nxtr1: JNB P2.1,nxtr2
       DJNZ r1, nxtr2
       CLR P2.0
nxtr2: JNB P2.1,nxtr3