Dashboard: BULB

       Name: BULB                                                    [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Draw an indicator bulb on the dashboard
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * ECBLB calls via BULB-2


 Arguments:

   A                    The y-coordinate of the bulb as a low-byte screen
                        address offset within screen page &7D (as both bulbs
                        are on this character row in the dashboard)

   (Y X)                The address of the character definition of the bulb to
                        be drawn (i.e. ECBT for the E.C.M. bulb, or SPBT for the
                        space station bulb)


 Other entry points:

   BULB-2               Set the Y screen address


.BULB

 STA SC                 \ Store the low byte of the screen address in SC

                        \ --- Mod: Code removed for Elite-A: ------------------>

\ STX P+1               \ Set P(2 1) = (Y X)
\ STY P+2
\
\ LDA #&7D              \ Set A to the high byte of the screen address, which is
\                       \ &7D as the bulbs are both in the character row from
\                       \ &7D00 to &7DFF

                        \ --- And replaced by: -------------------------------->

 LDA #&7D               \ Set A to the high byte of the screen address, which is
                        \ &7D as the bulbs are both in the character row from
                        \ &7D00 to &7DFF

 STX P+1                \ Set P(2 1) = (Y X)
 STY P+2

                        \ --- End of replacement ------------------------------>

 JMP RREN               \ Call RREN to print the character definition pointed to
                        \ by P(2 1) at the screen address pointed to by (A SC),
                        \ returning from the subroutine using a tail call