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Elite on the BBC Micro

Maths (Geometry): TAS6 (6502SP version)

Name: TAS6 [View in context] Type: Subroutine Category: Maths (Geometry) Summary: Negate the vector in XX15 so it points in the opposite direction
.TAS6 LDA XX15 \ Reverse the sign of the x-coordinate of the vector in EOR #%10000000 \ XX15 STA XX15 LDA XX15+1 \ Then reverse the sign of the y-coordinate EOR #%10000000 STA XX15+1 LDA XX15+2 \ And then the z-coordinate, so now the XX15 vector is EOR #%10000000 \ pointing in the opposite direction STA XX15+2 RTS \ Return from the subroutine