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⌂ ∞ ▽ Elite on the 6502

Version analysis of ABORT2

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

Code variations between these versions are shown below.

       Name: ABORT2
       Type: Subroutine
   Category: Dashboard
    Summary: Set/unset the lock target for a missile and update the dashboard



 Set the lock target for the leftmost missile and update the dashboard.



 Arguments:

   X                    The slot number of the ship to lock our missile onto, or
                        &FF to remove missile lock

Code variation 1 of 2A variation in the comments only

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

Cassette, Flight, Docked
6502SP, Master
Electron
   Y                    The new colour of the missile indicator:

                          * &00 = black (no missile)

                          * &0E = red (armed and locked)

                          * &E0 = yellow/white (armed)

                          * &EE = green/cyan (disarmed)

   Y                    The new colour of the missile indicator:

                          * &00 = black (no missile)

                          * #RED2 = red (armed and locked)

                          * #YELLOW2 = yellow/white (armed)

                          * #GREEN2 = green (disarmed)

   Y                    The new shape of the missile indicator:

                          * &04 = black (no missile)

                          * &11 = black "T" in white square (armed and locked)

                          * &0D = black box in white square (armed)

                          * &09 = white square (disarmed)




.ABORT2

 STX MSTG               \ Store the target of our missile lock in MSTG

 LDX NOMSL              \ Call MSBAR to update the leftmost indicator in the
 JSR MSBAR              \ dashboard's missile bar, which returns with Y = 0

 STY MSAR               \ Set MSAR = 0 to indicate that the leftmost missile
                        \ is no longer seeking a target lock

 RTS                    \ Return from the subroutine

Code variation 2 of 2Minor and very low-impact

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

Master
.msbpars

 EQUB 4, 0, 0, 0, 0     \ These bytes appear to be unused (they are left over
                        \ from the 6502 Second Processor version of Elite)