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⌂ ∞ ▽ Elite on the BBC Micro and NES

Dashboard: ADPARAMS

[6502 Second Processor version, I/O processor]

       Name: ADPARAMS                                                [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Implement the OSWRCH 137 <param> command (add a dashboard
             parameter and update the dashboard when all are received)

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * JMPTAB calls ADPARAMS




.ADPARAMS

 INC PARANO             \ PARANO points to the last free byte in PARAMS, which
                        \ is where we're about to store the new byte in A, so
                        \ increment PARANO to point to the byte after this one

 LDX PARANO             \ Store the new byte in A at position PARANO-1 in TABLE
 STA PARAMS-1,X         \ (which was the last free byte before we incremented
                        \ PARANO above)

 CPX #PARMAX            \ If X >= #PARMAX, skip the following instruction, as we
 BCS P%+3               \ have now received all the parameters we need to update
                        \ the dashboard

 RTS                    \ Otherwise we still have more parameters to receive, so
                        \ return from the subroutine

 JSR DIALS              \ Call DIALS to update the dashboard with the parameters
                        \ in PARAMS

 JMP PUTBACK            \ Jump to PUTBACK to restore the USOSWRCH handler and
                        \ return from the subroutine using a tail call