Text: Print234DigitBCD

       Name: Print234DigitBCD                                        [Show more]
       Type: Subroutine
   Category: Text
    Summary: Print a specific driver's accumulated points as a padded two-,
             three- or four-digit number
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * PrintDriverTable calls Print234DigitBCD


 Print (totalPointsHi totalPointsLo) for driver X as a four-digit number,
 followed by a space. The first two digits are printed as spaces if the high
 byte is zero, and the third digit is printed as a space if applicable.


.Print234DigitBCD

 LDA #2                 \ Print two spaces
 JSR PrintSpaces

 LDA #%00100000         \ Set G = %00100000, so if we print the high byte and
 STA G                  \ the first digit is 0, it will be replaced by a space

 LDA totalPointsHi,X    \ Set A to the X-th totalPointsHi value

 BNE Print4DigitBCD     \ If A is non-zero, jump to Print4DigitBCD to print the
                        \ (totalPointsHi totalPointsLo) for driver X as a
                        \ four-digit number

 LDA #2                 \ Otherwise print two spaces for the first two digits,
 JSR PrintSpaces        \ as the high byte is zero

 LSR G                  \ Shift G right one place to give to %00010000, so the
                        \ next call to Print2DigitBCD will print a space for the
                        \ first digit if it is zero

 BNE Print4DigitBCD+3   \ Jump to Print4DigitBCD+3 to print the second two
                        \ digits in totalPointsLo (this BNE is effectively a JMP
                        \ as the result of the LSR is never zero)