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⌂ ∞ Elite on the BBC Micro and NES

Flight: DENGY

[NES version, Bank 0]

       Name: DENGY                                                   [Show more]
       Type: Subroutine
   Category: Flight
    Summary: Drain some energy from the energy banks

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * FlightLoop4To16 calls DENGY
             * LASLI calls DENGY




 Returns:

   Z flag               Set if we have no energy left, clear otherwise



.DENGY

 DEC ENERGY             ; Decrement the energy banks in ENERGY

 PHP                    ; Save the flags on the stack

 BNE paen2              ; If the energy levels are not yet zero, skip the
                        ; following instruction

 INC ENERGY             ; The minimum allowed energy level is 1, and we just
                        ; reached 0, so increment ENERGY back to 1

.paen2

 PLP                    ; Restore the flags from the stack, so we return with
                        ; the Z flag from the DEC instruction above

 RTS                    ; Return from the subroutine