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⌂ ∞ Elite on the BBC Micro and NES

Flight: wW

[NES version, Bank 0]

       Name: wW                                                      [Show more]
       Type: Subroutine
   Category: Flight
    Summary: Start a hyperspace countdown

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * Ghy calls via wW2




 Start the hyperspace countdown (for both inter-system hyperspace and the
 galactic hyperdrive).



 Other entry points:

   wW2                  Start the hyperspace countdown, starting the countdown
                        from the value in A



.wW

 LDA #16                ; The hyperspace countdown starts from 16, so set A to
                        ; 15 so we can set the two hyperspace counters

.wW2

 STA QQ22+1             ; Set the number in QQ22+1 to A, which is the number
                        ; that's shown on-screen during the hyperspace countdown

 LDA #1                 ; Set the number in QQ22 to 11, which is the internal
 STA QQ22               ; counter that counts down by 1 each iteration of the
                        ; main game loop, and each time it reaches zero, the
                        ; on-screen counter gets decremented, and QQ22 gets set
                        ; to 5, so setting QQ22 to 1 here makes the first tick
                        ; of the hyperspace counter shorter than subsequent
                        ; ticks

 JMP UpdateIconBar_b3   ; Update the icon bar to remove the Hyperspace button,
                        ; as we are now commit to our hyperspace jump, and
                        ; return from the subroutine using a tail call