HD643303x Hitachi, HD643303x Datasheet - Page 39

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

2.5.2 Memory Data Formats
Figure 2-8 shows the data formats on memory. The H8/300H CPU can access word data and
longword data on memory, but word or longword data must begin at an even address. If an
attempt is made to access word or longword data at an odd address, no address error occurs but
the least significant bit of the address is regarded as 0, so the access starts at the preceding
address. This also applies to instruction fetches.
Data Type
Word data
Word data
Longword data
Legend
ERn:
En:
Rn:
RnH:
RnL:
MSB:
LSB:
General register
General register E
General register R
General register RH
General register RL
Most significant bit
Least significant bit
General
Register
Rn
En
ERn
Figure 2-7 General Register Data Formats (2)
MSB
MSB
MSB
Data Format
15
15
31
24
LSB
LSB
16
0
0
15
LSB
0