Flight: TT18

       Name: TT18                                                    [Show more]
       Type: Subroutine
   Category: Flight
    Summary: Try to initiate a jump into hyperspace
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * TT102 calls TT18


 Try to go through hyperspace. Called from TT102 in the main loop when the
 hyperspace countdown has finished.


.TT18

 JSR ResetMusicAfterNMI ; Wait for the next NMI before resetting the current
                        ; tune to 0 (no tune) and stopping the music

 LDA QQ14               ; Subtract the distance to the selected system (in QQ8)
 SEC                    ; from the amount of fuel in our tank (in QQ14) into A
 SBC QQ8

 BCS P%+4               ; If the subtraction didn't overflow, skip the next
                        ; instruction

 LDA #0                 ; The subtraction overflowed, so set A = 0 so we don't
                        ; end up with a negative amount of fuel

 STA QQ14               ; Store the updated fuel amount in QQ14

 LDA QQ11               ; If this is not the space view, then jump to hypr1 to
 BNE hypr1              ; skip drawing the hyperspace tunnel, but still make the
                        ; hyperspace sound

 JSR ClearScanner       ; Remove all ships from the scanner and hide the scanner
                        ; sprites

 JSR LL164_b6           ; Call LL164 to show the hyperspace tunnel and make the
                        ; hyperspace sound

 JMP hypr2              ; Jump to hypr2 to skip the following, as we already
                        ; the hyperspace sound in LL164

.hypr1

 JSR MakeHyperSound     ; Make the hyperspace sound for when we are not in the
                        ; space view

.hypr2

 LDA controller1Up      ; If either of the up or down buttons are being pressed,
 ORA controller1Down    ; then jump to MJP to force a mis-jump
 BMI MJP

.ee5

 JSR DORND              ; Set A and X to random numbers

 CMP #253               ; If A >= 253 (0.78% chance) then jump to MJP to trigger
 BCS MJP                ; a mis-jump into witchspace

 JSR hyp1               ; Jump straight to the system at (QQ9, QQ10)

 JSR WaitForNMI         ; Wait until the next NMI interrupt has passed (i.e. the
                        ; next VBlank)

 JSR RES2               ; Reset a number of flight variables and workspaces

 JSR SOLAR              ; Halve our legal status, update the missile indicators,
                        ; and set up data blocks and slots for the planet and
                        ; sun