WP1 (Flight) - Elite on the BBC Micro

       Name: WP1                                               [View in context]
       Type: Subroutine
   Category: Drawing planets
    Summary: Reset the ball line heap


.WP1

 LDA #1                 \ Set LSP = 1 to reset the ball line heap pointer
 STA LSP

 LDA #&FF               \ Set LSX2 = &FF to indicate the ball line heap is empty
 STA LSX2

 RTS                    \ Return from the subroutine

[X]

Variable LSP in workspace ZP

The ball line heap pointer, which contains the number of the first free byte after the end of the LSX2 and LSY2 heaps (see the deep dive on "The ball line heap" for details)

[X]

Variable LSX2 in workspace WP

The ball line heap for storing x-coordinates (see the deep dive on "The ball line heap" for details)