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⌂ ∞ ▽ Elite on the 6502

Version analysis of ABORT

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

Code variations between these versions are shown below.

       Name: ABORT
       Type: Subroutine
   Category: Dashboard
    Summary: Disarm missiles and update the dashboard indicators

Code variation 1 of 3A variation in the comments only

This variation is blank in the Electron version.

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

Cassette, Flight, Docked
6502SP, Master
 Arguments:

   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)

 Arguments:

   Y                    The new colour of the missile indicator:

                          * &00 = black (no missile)

                          * #RED2 = red (armed and locked)

                          * #YELLOW2 = yellow/white (armed)

                          * #GREEN2 = green (disarmed)

Code variation 2 of 3A variation in the comments only

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

Electron
 Other entry points:

   ABORT-2              Set the indicator to disarmed (white square)

Code variation 3 of 3Specific to an individual platform

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

Electron
 LDY #&09               \ Set Y = &09 so we set the missile to a white square
                        \ (disarmed)

.ABORT

 LDX #&FF               \ Set X to &FF, which is the value of MSTG when we have
                        \ no target lock for our missile

                        \ Fall through into ABORT2 to set the missile lock to
                        \ the value in X, which effectively disarms the missile