Version analysis of STARS - Elite on the BBC Micro and NES

This code appears in the following versions (click to see it in the source code):

Cassette, Disc (flight), 6502 Second Processor, Master and Electron

Code variations between these versions are shown below.

       Name: STARS
       Type: Subroutine
   Category: Stardust
    Summary: The main routine for processing the stardust


 Called at the very end of the main flight loop.


.STARS

Code variation 1 of 1Related to the screen mode

This variation is blank in the Disc (flight), 6502 Second Processor and Electron versions.

Tap on a block to expand it, and tap it again to revert.

Cassette
Master
\LDA #&FF               \ These instructions are commented out in the original
\STA COL                \ source, but they would set the stardust colour to
                        \ white. That said, COL is only used when updating the
                        \ dashboard, so this would have no effect - perhaps it's
                        \ left over from experiments with a colour top part of
                        \ the screen? Who knows...
 LDA #DUST              \ Switch to stripe 3-2-3-2, which is cyan/red in the
 STA COL                \ space view

 LDX VIEW               \ Load the current view into X:
                        \
                        \   0 = front
                        \   1 = rear
                        \   2 = left
                        \   3 = right

 BEQ STARS1             \ If this 0, jump to STARS1 to process the stardust for
                        \ the front view

 DEX                    \ If this is view 2 or 3, jump to STARS2 (via ST11) to
 BNE ST11               \ process the stardust for the left or right views

 JMP STARS6             \ Otherwise this is the rear view, so jump to STARS6 to
                        \ process the stardust for the rear view

.ST11

 JMP STARS2             \ Jump to STARS2 for the left or right views, as it's
                        \ too far for the branch instruction above