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⌂ ∞ ▽ Elite on the BBC Micro and NES

Dashboard: DIALS (Part 1 of 4)

[Acorn Electron version]

       Name: DIALS (Part 1 of 4)                                     [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Update the dashboard: speed indicator
  Deep dive: The dashboard indicators

    Context: See this subroutine in context in the source code
 Variations: See code variations for this subroutine in the different versions
 References: This subroutine is called as follows:
             * EQSHP calls DIALS
             * Main game loop (Part 5 of 6) calls DIALS
             * RES2 calls DIALS




 This routine updates the dashboard. First we draw all the indicators in the
 right part of the dashboard, from top (speed) to bottom (energy banks), and
 then we move on to the left part, again drawing from top (forward shield) to
 bottom (altitude).

 This first section starts us off with the speedometer in the top right.



.DIALS

 LDA #&F0               \ Set SC(1 0) = &76F0, which is the screen address for
 STA SC                 \ the character block containing the left end of the
 LDA #&76               \ top indicator in the right part of the dashboard, the
 STA SC+1               \ one showing our speed

 LDA DELTA              \ Fetch our ship's speed into A, in the range 0-40

 JSR DIL                \ Draw the speed indicator using a range of 0-31, and
                        \ increment SC to point to the next indicator (the roll
                        \ indicator)