Routines
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BE08: Negate Number
Used by the routines at ApplyPlayerCollision, BounceShip, ReverseObjectSpeed, StartCrystalObject, ReverseAndHalveSpeed, CheckTerrainCollision and DrawShipTop.
Changes the sign of a signed number.
Input
HL Number
Output
HL Number with the sign changed
NegateNumber BE08 LD A,H A=H.
BE09 CPL Invert A.
BE0A LD H,A H=A.
BE0B LD A,L A=L.
BE0C CPL Invert A.
BE0D LD L,A L=A.
BE0E INC HL Advance HL.
BE0F RET Return.
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