Flight: hyp

       Name: hyp                                                     [Show more]
       Type: Subroutine
   Category: Flight
    Summary: Start the hyperspace process
    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:
             * TT102 calls hyp
             * TTX110 calls via TTX111


 Called when "H" or CTRL-H is pressed during flight. Checks the following:

   * We are in space

   * We are not already in a hyperspace countdown

 If CTRL is being held down, we jump to Ghy to engage the galactic hyperdrive,
 otherwise we check that:

   * The selected system is not the current system

   * We have enough fuel to make the jump

 and if all the pre-jump checks are passed, we print the destination on-screen
 and start the countdown.


 Other entry points:

   TTX111               Used to rejoin this routine from the call to TTX110


.hyp

 LDA QQ12               \ If we are docked (QQ12 = &FF) then jump to dockEd to
 BNE dockEd             \ print an error message and return from the subroutine
                        \ using a tail call (as we can't hyperspace when docked)

 LDA QQ22+1             \ Fetch QQ22+1, which contains the number that's shown
                        \ on-screen during hyperspace countdown

 BEQ P%+3               \ If it is zero, skip the next instruction

 RTS                    \ The count is non-zero, so return from the subroutine

 LDA #CYAN              \ The count is zero, so send a #SETCOL CYAN command to
 JSR DOCOL              \ the I/O processor to switch to colour 3, which is cyan
                        \ in the space view

 JSR CTRL               \ Scan the keyboard to see if CTRL is currently pressed

 BMI Ghy                \ If it is, then the galactic hyperdrive has been
                        \ activated, so jump to Ghy to process it

 LDA QQ11               \ If the current view is 0 (i.e. the space view) then
 BEQ TTX110             \ jump to TTX110, which calls TT111 to set the current
                        \ system to the nearest system to (QQ9, QQ10), and jumps
                        \ back into this routine at TTX111 below

 AND #%11000000         \ If either bit 6 or 7 of the view type is set - so
 BNE P%+3               \ this is either the Short-range or Long-range Chart -
                        \ then skip the following instruction

 RTS                    \ This is not a chart view, so return from the
                        \ subroutine

 JSR hm                 \ This is a chart view, so call hm to redraw the chart
                        \ crosshairs

.TTX111

                        \ If we get here then the current view is either the
                        \ space view or a chart

 LDA QQ8                \ If either byte of the distance to the selected system
 ORA QQ8+1              \ in QQ8 are zero, skip the next instruction to make a
 BNE P%+3               \ copy of the destination seeds in safehouse

 RTS                    \ The selected system is the same as the current system,
                        \ so return from the subroutine

 LDX #5                 \ We now want to copy those seeds into safehouse, so we
                        \ so set a counter in X to copy 6 bytes

.sob

 LDA QQ15,X             \ Copy the X-th byte of QQ15 into the X-th byte of
 STA safehouse,X        \ safehouse

 DEX                    \ Decrement the loop counter

 BPL sob                \ Loop back to copy the next byte until we have copied
                        \ all six seed bytes

 LDA #7                 \ Move the text cursor to column 7, row 23 (in the
 JSR DOXC               \ middle of the bottom text row)
 LDA #23
 JSR DOYC

 LDA #0                 \ Set QQ17 = 0 to switch to ALL CAPS
 STA QQ17

 LDA #189               \ Print recursive token 29 ("HYPERSPACE ")
 JSR TT27

IF _EXECUTIVE

 BIT JUMP               \ If infinite jump range is configured, then jump down
 BMI goTT147+3          \ to IJUMP so we do the jump whatever the distance

ENDIF

 LDA QQ8+1              \ If the high byte of the distance to the selected
 BNE goTT147            \ system in QQ8 is > 0, then it is definitely too far to
                        \ jump (as our maximum range is 7.0 light years, or a
                        \ value of 70 in QQ8(1 0)), so jump to TT147 via goTT147
                        \ to print "RANGE?" and return from the subroutine using
                        \ a tail call

 LDA QQ14               \ Fetch our current fuel level from Q114 into A

 CMP QQ8                \ If our fuel reserves are greater than or equal to the
 BCS P%+5               \ distance to the selected system, then we have enough
                        \ fuel for this jump, so skip the following instruction
                        \ to start the hyperspace countdown

.goTT147

 JMP TT147              \ We don't have enough fuel to reach the destination, so
                        \ jump to TT147 to print "RANGE?" and return from the
                        \ subroutine using a tail call

 LDA #'-'               \ Print a hyphen
 JSR TT27

 JSR cpl                \ Call cpl to print the name of the selected system

                        \ Fall through into wW to start the hyperspace countdown