Dashboard: IndicatorB

       Name: IndicatorB                                              [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Update the brakes indicator ("B")
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * NewGame calls IndicatorB
             * UpdateFlightModel (Part 3 of 4) calls IndicatorB


.IndicatorB

 LDA #%01110111         \ Set A to a four-pixel block with pixels 0, 1 and 2 in
                        \ white, to act as the centre of the brakes indicator
                        \ when turned on

 LDX brakesStatus       \ If brakesStatus is non-zero then the brakes are on, so
 BNE indb1              \ jump to indb1

 LDA #%01010101         \ Set A to a four-pixel block with pixels 0 and 2 in
                        \ white, to act as the centre of the brakes indicator
                        \ when turned off

.indb1

 LDX #2                 \ Set X = 2 to use as a pixel row counter for the three
                        \ pixel rows in the brakes indicator

.indb2

 STA row30_char37_2,X   \ Update pixel row X of the brakes indicator to the
                        \ pixel pattern in A

 DEX                    \ Decrement the byte counter to the pixel row above

 BPL indb2              \ Loop back to update the next row of the indicator

 RTS                    \ Return from the subroutine