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⌂ ∞ Elite on the BBC Micro and NES

Status: EXNO2

[BBC Master version]

       Name: EXNO2                                                   [Show more]
       Type: Subroutine
   Category: Status
    Summary: Process us making a kill
  Deep dive: Combat rank

    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:
             * Main flight loop (Part 5 of 16) calls EXNO2
             * Main flight loop (Part 11 of 16) calls EXNO2
             * TACTICS (Part 1 of 7) calls EXNO2




 We have killed a ship, so increase the kill tally, displaying an iconic
 message of encouragement if the kill total is a multiple of 256, and then
 make a nearby explosion sound.



 Arguments:

   X                    The type of the ship that was killed



.EXNO2

 LDA TALLYL             \ We now add the fractional kill count to our tally,
 CLC                    \ starting with the fractional bytes:
 ADC KWL%-1,X           \
 STA TALLYL             \   TALLYL = TALLYL + fractional kill count
                        \
                        \ where the fractional kill count is taken from the
                        \ KWL% table, according to the ship's type (we look up
                        \ the X-1-th value from KWL% because ship types start
                        \ at 1 rather than 0)

 LDA TALLY              \ And then we add the low byte of TALLY(1 0):
 ADC KWH%-1,X           \
 STA TALLY              \   TALLY = TALLY + carry + integer kill count
                        \
                        \ where the integer kill count is taken from the KWH%
                        \ table in the same way

 BCC davidscockup       \ If there is no carry, jump straight to EXNO3 to skip
                        \ the following three instructions

 INC TALLY+1            \ Increment the high byte of the kill count in TALLY

 LDA #101               \ The kill total is a multiple of 256, so it's time
 JSR MESS               \ for a pat on the back, so print recursive token 101
                        \ ("RIGHT ON COMMANDER!") as an in-flight message

.davidscockup

                        \ Fall through into EXNO3 to make the sound of a
                        \ ship exploding