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BBC Micro Elite

Drawing circles: LL164 (6502SP version)

Name: LL164 [View in context] Type: Subroutine Category: Drawing circles Summary: Make the hyperspace sound and draw the hyperspace tunnel
See the IRQ1 routine for details on the multi-coloured effect that's used.
.LL164 LDA #56 \ Call the NOISE routine with A = 56 to make the sound JSR NOISE \ of the hyperspace drive being engaged LDA #DOhfx \ Send a #DOhfx 1 command to the I/O processor to tell JSR OSWRCH \ it to show hyperspace colours in the top part of the LDA #1 \ screen JSR OSWRCH LDA #4 \ Set the step size for the hyperspace rings to 4, so \ there are more sections in the rings and they are \ quite round (compared to the step size of 8 used in \ the much more polygonal launch rings) JSR HFS2 \ Call HFS2 to draw the hyperspace tunnel rings LDA #DOhfx \ Send a #DOhfx 0 command to the I/O processor to tell JSR OSWRCH \ it to show normal colours in the top part of the LDA #0 \ screen, returning from the subroutine using a tail JMP OSWRCH \ call