Score bar: PrintHexDigit

       Name: PrintHexDigit                                           [Show more]
       Type: Subroutine
   Category: Score bar
    Summary: An unused routine that prints a single digit hexadecimal number in
             the score bar
  Deep dive: Unused code in Lander
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * PrintHexNumber calls PrintHexDigit


 Arguments:

   R0                               The number to print (only the low nibble is
                                    printed, the rest of the number is ignored)


.PrintHexDigit

 AND     R0, R0, #&F                \ Extract the low nibble from the number in
                                    \ R0

 CMP     R0, #&A                    \ If the low nibble in R0 >= &A then the hex
 ADDHS   R0, R0, #&37               \ digit is A to F, so add &37 to get the
                                    \ corresponding hex digit (so this converts
                                    \ &A into ASCII &37 + &A = &41, which gives
                                    \ us "A", the hex digit we want)

 ADDLO   R0, R0, #&30               \ Otherwise the low nibble in R0 is 0 to 9,
                                    \ so add the ASCII value of "0" (ASCII &30)
                                    \ to get the corresponding hex digit

 SWI     OS_WriteC                  \ Print the character in R0

 MOV     PC, R14                    \ Return from the subroutine