Flight: DENGY

       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:
             * LASLI calls DENGY
             * Main flight loop (Part 16 of 16) 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 P%+5               ; 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

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

 RTS                    ; Return from the subroutine