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⌂ ∞ ▽ Elite on the BBC Micro and NES

Drawing circles: LL164

[6502 Second Processor version]

       Name: LL164                                                   [Show more]
       Type: Subroutine
   Category: Drawing circles
    Summary: Make the hyperspace sound and draw the hyperspace tunnel

    Context: See this subroutine in context in the source code
 Variations: See code variations for this subroutine in the different versions
 References: This subroutine is called as follows:
             * MJP calls LL164
             * TT18 calls LL164




 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