L4 BSET PC 3 - ORG @ 4 + ! ( find )
( find word the same name as str in SI starting from tip in
  BX. Returns wordref in BX. Z if found, NZ if not. )
    CH CH XORrr, CL [SI] MOVr[], ( CX -> strlen )
    SI INCx,
    AX AX XORxx, ( initial prev )
    BEGIN, ( inner )
        BX AX SUBxx, ( jump to prev wordref )
        BX DECx, AL [BX] MOVr[], ( strlen )
        CL AL CMPrr, IFZ, BX INCx, RETn, THEN,
        BX DECx, BX DECx, AX [BX] MOVx[], ( prev )
        AX AX ORxx,
    JNZ, AGAIN,
    BEGIN, JMPs, AGAIN,