Main loop: Main flight loop (Part 13 of 16)

       Name: Main flight loop (Part 13 of 16)                        [Show more]
       Type: Subroutine
   Category: Main loop
    Summary: Charge shields and energy banks
  Deep dive: Program flow of the main game loop
             Scheduling tasks with the main loop counter
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 The main flight loop covers most of the flight-specific aspects of Elite. This
 section covers the following:

   * Charge shields and energy banks (every 7 iterations of the main loop)


.MA18

.MA77

 LDA MCNT               \ Fetch the main loop counter and calculate MCNT mod 8,
 AND #7                 \ jumping to MA22 if it is non-zero (so the following
 BNE MA22               \ code only runs every 8 iterations of the main loop)

 LDX ENERGY             \ Fetch our ship's energy levels and skip to b if bit 7
 BPL b                  \ is not set, i.e. only charge the shields from the
                        \ energy banks if they are at more than 50% charge

 LDX ASH                \ Call SHD to recharge our aft shield and update the
 JSR SHD                \ shield status in ASH
 STX ASH

 LDX FSH                \ Call SHD to recharge our forward shield and update
 JSR SHD                \ the shield status in FSH
 STX FSH

.b

 SEC                    \ Set A = ENERGY + ENGY + 1, so our ship's energy
 LDA ENGY               \ level goes up by the correct amount for our current
 ADC ENERGY             \ ship, depending on whether we have an energy unit
                        \ fitted

 BCS P%+5               \ If the value of A did not overflow (the maximum
 STA ENERGY             \ energy level is &FF), then store A in ENERGY