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⌂ ∞ Elite on the BBC Micro and NES

Dashboard: SCANCOL

[BBC Micro disc version, Flight]

       Name: SCANCOL                                                 [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Set the correct colour on the scanner for the current ship type

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * SCAN calls SCANCOL




 This routine sets the scanner colours as follows:

  * Missiles = yellow/white

  * Ships = green/cyan

  * Space station, asteroids, splinters, escape pods and cargo = red

 This is different from the original disc variant, where red is not used (the
 space station, asteroids, splinters, escape pods and cargo are green/cyan in
 the original).



 Arguments:

   A                    The ship type that we are showing on the scanner



IF _SRAM_DISC

.SCANCOL

 LDX #&F0               \ Set X to the default scanner colour of yellow/white
                        \ (a 4-pixel mode 5 byte in colour 2)

 CMP #MSL               \ If the ship type in A is that of a missile, then jump
 BEQ scol1              \ to scol1 to return from the subroutine with the colour
                        \ set to yellow/white

 LDX #&FF               \ Set X to the default scanner colour of green/cyan
                        \ (a 4-pixel mode 5 byte in colour 3)

 CMP #SHU               \ If the ship type in A is that of a Shuttle or greater,
 BCS scol1              \ then it is a ship, so jump to scol1 to return from the
                        \ subroutine with the colour set to green/cyan

 LDX #&0F               \ Otherwise set X to the default scanner colour of red
                        \ (a 4-pixel mode 5 byte in colour 1), to use as the
                        \ scanner colour for the space station, asteroids,
                        \ escape pods and cargo

.scol1

 RTS                    \ Return from the subroutine

 NOP                    \ This code is never run, and just pads out the DEEOR
 NOP                    \ routine in the sideways RAM variant to be the same
 NOP                    \ size as in the original version (the sideways RAM
 NOP                    \ variant is not encrypted, so the decryption routine
 NOP                    \ is disabled and is replaced by NOPs and the SCANCOL
 JMP RSHIPS             \ routine)

ENDIF