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2.4.3 BCD (Binary-coded Decimal)
(1) Definition
BCD is a numeral system that uses four binary bits to represent the decimal digits 0 through 9.
The difference from hexadecimal is that BCD does not use letters A to F.
Table2.5
shows the numeric representations in BIN, BCD, and DEC.
(2) Numeric representation in BCD
Each register (such as the data register, link register) in the CPU module consists of 16 bits.
Therefore, the numeric values can be stored in each register are those in the range between 0 to 9999 in BCD.
Table2.5 Numeric representations in BIN,BCD,and DEC
DEC (Decimal) BIN (Binary) BCD (Binary-coded Decimal)
0 0000 0
1 0001 1
20010 10
3 0011 11
4 0100 100
5 0101 101
6 0110 110
7 0111 111
8 1000 1000
9 1001 1001
10 1010 1 0000
11 1011 1 0001
12 1100 1 0010
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