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⌂ ∞ Elite on the BBC Micro and NES

Universe: NWSPS

[NES version, Bank 0]

       Name: NWSPS                                                   [Show more]
       Type: Subroutine
   Category: Universe
    Summary: Add a new space station to our local bubble of universe

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * SpawnSpaceStation calls NWSPS
             * TT110 calls NWSPS




.NWSPS

 LDX #%10000001         ; Set the AI flag in byte #32 to %10000001 (hostile,
 STX INWK+32            ; no AI, has an E.C.M.)

 LDX #0                 ; Set pitch counter to 0 (no pitch, roll only)
 STX INWK+30

 STX NEWB               ; Set NEWB to %00000000, though this gets overridden by
                        ; the default flags from E% in NWSHP below

 STX FRIN+1             ; Set the second slot in the FRIN table to 0, so when we
                        ; fall through into NWSHP below, the new station that
                        ; gets created will go into slot FRIN+1, as this will be
                        ; the first empty slot that the routine finds

 DEX                    ; Set the roll counter to 255 (maximum anti-clockwise
 STX INWK+29            ; roll with no damping)

 LDX #10                ; Call NwS1 to flip the sign of nosev_x_hi (byte #10)
 JSR NwS1

 JSR NwS1               ; And again to flip the sign of nosev_y_hi (byte #12)

 JSR NwS1               ; And again to flip the sign of nosev_z_hi (byte #14)

 LDA #SST               ; Set A to the space station type, and fall through
                        ; into NWSHP to finish adding the space station to the
                        ; universe

 JSR NWSHP              ; Call NWSHP to add the space station to the universe

 LDX XX21+2*SST-2       ; Set (Y X) to the address of the Coriolis station's
 LDY XX21+2*SST-1       ; ship blueprint

 LDA tek                ; If the system's tech level in tek is less than 10,
 CMP #10                ; jump to notadodo, so tech levels 0 to 9 have Coriolis
 BCC notadodo           ; stations, while 10 and above will have Dodo stations

 LDX XX21+2*DOD-2       ; Set (Y X) to the address of the Dodo station's ship
 LDY XX21+2*DOD-1       ; blueprint

.notadodo

 STX spasto             ; Store the address of the space station in spasto(1 0)
 STY spasto+1           ; so we spawn the correct type of station in part 4 of
                        ; the main flight loop

 JMP UpdateIconBar_b3   ; Update the icon bar so the docking computer icon gets
                        ; displayed to reflect that we are in the station's safe
                        ; zone, returning from the subroutine using a tail call