2.3.1 Data Formats in General Registers
Data of all the sizes above can be stored in general registers as shown in figure 2-3.
Figure 2-3 Register Data Formats
7
6
5
4
3
2
1
0
don’t care
Data Type
Register No.
Data Format
7
0
1-bit data
RnH
7
6
5
4
3
2
1
0
don’t care
7
0
1-bit data
RnL
MSB
LSB
don’t care
7
0
Byte data
RnH
Byte data
RnL
Word data
Rn
4-bit BCD data
RnH
4-bit BCD data
RnL
Notation:
RnH:
RnL:
MSB:
LSB:
Upper byte of general register
Lower byte of general register
Most significant bit
Least significant bit
MSB
LSB
don’t care
7
0
MSB
LSB
15
0
Upper digit
Lower digit
don’t care
7
0
3
4
don’t care
Upper digit
Lower digit
7
0
3
4
18