6-digit HexToDec subroutine, used to write a player's score into status bar (note: although the score is shown in-game as 7 digits, the 7th digit is just a static 0 tile). This function calculates the digits by repeatedly subtracting powers of 10 (in hexadecimal) from the input number until no more can be subtracted.
Input:
- Y: Set to #$00
- X: Status bar position to write to (indexed from $0F15)
- $00-$03: Hexadecimal value to convert. Note that this is not provided as a normal 32-bit value, though, and instead should be provided as two 16-bit values, with $00 being the high word and $02 being the low word.
