CODE (br)
L1 BSET ( used in ?br and loop )
    LDA(BC), H 0 LDri, L A LDrr,
    RLA, IFC, H DECr, THEN,
    BC ADDHLd, B H LDrr, C L LDrr,
;CODE
CODE (?br)
    HL POP,
    HLZ,
    JRZ, L1 BWR ( br + 1. False, branch )
    ( True, skip next byte and don't branch )
    BC INCd,
;CODE