41
2.5
Data Formats
The CPU can process 1-bit, 4-bit (BCD), 8-bit (byte), 16-bit (word), and 32-bit (longword) data.
Bit-manipulation instructions operate on 1-bit data by accessing bit n (n = 0, 1, 2, …, 7) of byte
operand data. The DAA and DAS decimal-adjust instructions treat byte data as two digits of 4-bit
BCD data.
2.5.1
General Register Data Formats
Figure 2-10 shows the data formats in general registers.
7 6 5 4 3 2 1 0
Don’t care
7
0
Don’t care
7 6 5 4 3 2 1 0
4 3
7
0
7
0
Don’t care
Upper
Lower
LSB
MSB
LSB
Data Type
Register Number
Data Format
1-bit data
1-bit data
4-bit BCD data
4-bit BCD data
Byte data
Byte data
RnH
RnL
RnH
RnL
RnH
RnL
MSB
Don’t care
Upper
Lower
4 3
7
0
Don’t care
7
0
Don’t care
7
0
Figure 2-10 General Register Data Formats
Summary of Contents for H8S/2645
Page 4: ......
Page 16: ......
Page 58: ...26 ...
Page 110: ...78 ...
Page 120: ...88 ...
Page 132: ...100 ...
Page 160: ...128 ...
Page 172: ...140 ...
Page 418: ...386 ...
Page 444: ...412 ...
Page 530: ...498 ...
Page 562: ...530 ...
Page 642: ...610 ...
Page 662: ...630 ...
Page 688: ...656 ...
Page 756: ...724 ...
Page 784: ...752 ...
Page 812: ...780 ...
Page 837: ...805 A 2 Instruction Codes Table A 2 shows the instruction codes ...
Page 1152: ...1120 ...