▁algorithm , ▁the ▁ABC ▁ 8 0 ▁was ▁slow ▁on ▁B M 8 ▁( which ▁was ▁fixed ▁in ▁the ▁ABC ▁ 8 0 0 ). ▁Comp ared ▁to ▁the ▁cheap ▁S inc la ir ▁Z X 8 1 , ▁the ▁ABC ▁ 8 0 ▁was ▁actually ▁ ▁as ▁fast ▁on ▁the ▁simple ▁loop ▁of ▁B M 1 ▁( with ▁the ▁Z X 8 1 ▁running ▁in ▁fast ▁mode , ▁i . e . ▁without ▁a ▁continuous ▁TV - picture ). ▁ ▁Sound ▁▁ ▁S ine , ▁noise , ▁square ▁wave . ▁And ▁mixing ▁these . ▁ ▁Quick ▁decay , ▁s ine ▁overlay , ▁high ▁or ▁low ▁tone , ▁pul se ▁tone ▁control , ▁on ▁and ▁off . ▁ ▁Books ▁on ▁ABC ▁ 8 0 ▁The ▁circuit ry ▁in ▁the ▁ABC ▁ 8 0 ▁is ▁described ▁in ▁detail ▁in ▁the ▁book ▁Mik rod ator ns ▁ABC ▁( The ▁micro comput er ▁ABC ), ▁by ▁G unn ar ▁Mark es jö . ▁It ▁starts ▁off ▁with ▁a ▁course ▁in ▁digital ▁electron ics ▁and ▁micro comput er ▁principles ▁( ass uming ▁some ▁general ▁knowledge ▁in ▁electron ics ) ▁and ▁then ▁presents ▁a ▁large ▁number ▁of ▁block ▁diag rams ▁and ▁partial ▁circuit ▁sch emat ics , ▁covering ▁most ▁of ▁the ▁computer , ▁along ▁with ▁detailed ▁explan ations ▁of ▁how ▁it ▁works ▁and ▁why ▁certain ▁solutions ▁were ▁chosen . ▁ ▁See ▁also ▁▁ ▁ABC ▁ 8 0 0 ▁ ▁ABC ▁ 1 6 0 0 ▁- ▁Unix ▁based ▁ ▁References ▁ ▁External ▁links ▁▁▁▁ ▁ABC ▁user ▁group ▁(