qBCD

                         BCD
                Binary-Coded Decimal
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BCD is a way to represent decimal numbers in a more
compact way than ASCII text. One byte represents two
digits:

  01H = 1 decimal
  20H = 20 decimal (not 32)
  99H = 99 decimal (not 153)
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■ BCD is used rarely on PCs and in PC programming.
■ Note that hex digits A-F are never used, so numbers
  such as 0aH or b1H are invalid as BCD values.