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⌂ ∞ Elite on the BBC Micro and NES

Main loop: Main flight loop (Part 6 of 16)

[NES version, Bank 0]

       Name: Main flight loop (Part 6 of 16)                         [Show more]
       Type: Subroutine
   Category: Main loop
    Summary: For each nearby ship: Move the ship in space and copy the updated
             INWK data block back to K%
  Deep dive: Program flow of the main game loop
             Program flow of the ship-moving routine
             Ship data blocks

    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file




 The main flight loop covers most of the flight-specific aspects of Elite. This
 section covers the following:

   * Continue looping through all the ships in the local bubble, and for each
     one:

     * Move the ship in space

     * Copy the updated ship's data block from INWK back to K%



.MA21

 JSR MVEIT              ; Call MVEIT to move the ship we are processing in space

 SETUP_PPU_FOR_ICON_BAR ; If the PPU has started drawing the icon bar, configure
                        ; the PPU to use nametable 0 and pattern table 0

                        ; Now that we are done processing this ship, we need to
                        ; copy the ship data back from INWK to the correct place
                        ; in the K% workspace. We already set INF in part 4 to
                        ; point to the ship's data block in K%, so we can simply
                        ; do the reverse of the copy we did before, this time
                        ; copying from INWK to INF

 LDY #NI%-1             ; Set a counter in Y so we can loop through the NI%
                        ; bytes in the ship data block

.MAL3

 LDA INWK,Y             ; Load the Y-th byte of INWK and store it in the Y-th
 STA (INF),Y            ; byte of INF

 DEY                    ; Decrement the loop counter

 BPL MAL3               ; Loop back for the next byte, until we have copied the
                        ; last byte from INWK back to INF

 SETUP_PPU_FOR_ICON_BAR ; If the PPU has started drawing the icon bar, configure
                        ; the PPU to use nametable 0 and pattern table 0