Version analysis of DIALS (Part 4 of 4)

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

Cassette, Disc (flight), Disc (docked), 6502 Second Processor, Master and Electron

Code variations between these versions are shown below.

       Name: DIALS (Part 4 of 4)
       Type: Subroutine
   Category: Dashboard
    Summary: Update the dashboard: shields, fuel, laser & cabin temp, altitude
  Deep dive: The dashboard indicators

Code variation 1 of 9Related to the screen mode

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

Cassette, Flight, Docked
6502SP, Master
Electron
 LDA #&78               \ Set SC(1 0) = &7810, which is the screen address for
 STA SC+1               \ the character block containing the left end of the
 LDA #&10               \ top indicator in the left part of the dashboard, the
 STA SC                 \ one showing the forward shield
 LDA #&70               \ Set SC(1 0) = &7020, which is the screen address for
 STA SC+1               \ the character block containing the left end of the
 LDA #&20               \ top indicator in the left part of the dashboard, the
 STA SC                 \ one showing the forward shield
 LDA #&76               \ Set SC(1 0) = &7630, which is the screen address for
 STA SC+1               \ the character block containing the left end of the
 LDA #&30               \ top indicator in the left part of the dashboard, the
 STA SC                 \ one showing the forward shield

 LDA FSH                \ Draw the forward shield indicator using a range of
 JSR DILX               \ 0-255, and increment SC to point to the next indicator
                        \ (the aft shield)

 LDA ASH                \ Draw the aft shield indicator using a range of 0-255,
 JSR DILX               \ and increment SC to point to the next indicator (the
                        \ fuel level)

Code variation 2 of 9Related to the screen mode

This variation is blank in the Cassette, Disc (flight), Disc (docked) and Electron versions.

6502SP, Master
 LDA #YELLOW2           \ Set K (the colour we should show for high values) to
 STA K                  \ yellow

 STA K+1                \ Set K+1 (the colour we should show for low values) to
                        \ yellow, so the fuel indicator always shows in this
                        \ colour

 LDA QQ14               \ Draw the fuel level indicator using a range of 0-63,
 JSR DILX+2             \ and increment SC to point to the next indicator (the
                        \ cabin temperature)

Code variation 3 of 9Related to the screen mode

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

Cassette, Flight, Docked
6502SP, Master
Electron
 JSR PZW                \ Call PZW to set A to the colour for dangerous values
                        \ and X to the colour for safe values
 JSR PZW2               \ Call PZW2 to set A to the colour for dangerous values
                        \ and X to the colour for safe values, suitable for
                        \ non-striped indicators
 SEC                    \ Call NEXTR with the C flag set to move the screen
 JSR NEXTR              \ address in SC(1 0) down by one character row

Code variation 4 of 9Related to the Electron version

The Electron version doesn't include suns, so although there is a cabin temperature indicator in the dashboard, it never registers any temperature increases as the relevant code is missing.

This variation is blank in the Electron version.

Cassette, Flight, Docked, 6502SP, Master
 STX K+1                \ Set K+1 (the colour we should show for low values) to
                        \ X (the colour to use for safe values)

 STA K                  \ Set K (the colour we should show for high values) to
                        \ A (the colour to use for dangerous values)

                        \ The above sets the following indicators to show red
                        \ for high values and yellow/white for low values, which
                        \ we use for the cabin and laser temperature bars

 LDX #11                \ Set T1 to 11, the threshold at which we change the
 STX T1                 \ cabin and laser temperature indicators' colours

 LDA CABTMP             \ Draw the cabin temperature indicator using a range of
 JSR DILX               \ 0-255, and increment SC to point to the next indicator
                        \ (the laser temperature)

 LDA GNTMP              \ Draw the laser temperature indicator using a range of
 JSR DILX               \ 0-255, and increment SC to point to the next indicator
                        \ (the altitude)

Code variation 5 of 9A variation in the comments only

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

Cassette, Flight, Docked, 6502SP, Master
Electron
 LDA #240               \ Set T1 to 240, the threshold at which we change the
 STA T1                 \ altitude indicator's colour. As the altitude has a
                        \ range of 0-255, pixel 16 will not be filled in, and
                        \ 240 would change the colour when moving between pixels
                        \ 15 and 16, so this effectively switches off the colour
                        \ change for the altitude indicator
 LDA #240               \ Set T1 to 240, which would set the threshold at which
 STA T1                 \ we change the altitude indicator's colour in the other
                        \ versions, but it has no effect here, as the Electron
                        \ version doesn't support indicator colour changes

Code variation 6 of 9Related to the screen mode

This variation is blank in the Cassette, Disc (flight), Disc (docked) and Electron versions.

6502SP, Master
 LDA #YELLOW2           \ Set K (the colour we should show for high values) to
 STA K                  \ yellow

Code variation 7 of 9Minor and very low-impact

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

Cassette, Flight, Master
Docked
6502SP
Electron
 STA K+1                \ Set K+1 (the colour we should show for low values) to
                        \ 240, or &F0 (dashboard colour 2, yellow/white), so the
                        \ altitude indicator always shows in this colour

 LDA ALTIT              \ Draw the altitude indicator using a range of 0-255
 JSR DILX
 STA K+1                \ Set K+1 (the colour we should show for low values) to
                        \ 240, or &F0 (dashboard colour 2, yellow/white), so the
                        \ altitude indicator always shows in this colour

 LDA ALTIT              \ Draw the altitude indicator using a range of 0-255,
 JMP DILX               \ returning from the subroutine using a tail call
 STA K+1                \ Set K+1 (the colour we should show for low values) to
                        \ yellow, so the altitude indicator always shows in this
                        \ colour

 LDA ALTIT              \ Draw the altitude indicator using a range of 0-255,
 JMP DILX               \ returning from the subroutine using a tail call
 STA K+1                \ This sets K+1 to 240, which would set the colour to
                        \ show for low values in the other versions, but it has
                        \ no effect here, as the Electron version doesn't
                        \ support indicator colour changes

 LDA ALTIT              \ Draw the altitude indicator using a range of 0-255
 JSR DILX

Code variation 8 of 9Specific to an individual platform

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

Master
 LDA #%00001001         \ Clear bits 1 and 2 of the Access Control Register at
 STA VIA+&34            \ SHEILA &34 to switch main memory back into &3000-&7FFF

Code variation 9 of 9Specific to an individual platform

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

Cassette, Flight, Master, Electron
 JMP COMPAS             \ We have now drawn all the indicators, so jump to
                        \ COMPAS to draw the compass, returning from the
                        \ subroutine using a tail call