2.14. 2.14 Binary Coded Decimal (BCD) Representation
Although the integer and floating point formats cover most of the numeric needs of an average program, there are some special cases where other numeric representations are convenient. In this section we'll discuss the binary coded decimal (BCD) format because the 80×86 CPU provides a small amount of hardware support for this data representation.
BCD values are a sequence of nibbles with each nibble representing a value in the range 0..9. Of course, you can represent values in the range 0..15 using a nibble; the BCD format, however, uses only 10 of the possible 16 different values for each nibble.
Each nibble in a BCD value represents a single decimal digit. Therefore, with a single byte (i.e., ...
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