Figure 1-10 General Register Data Formats (cont)
1.5.2 Memory Data Formats
Figure 1-11 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.
0
MSB
LSB
15
Word data
Word data
Rn
En
0
LSB
15
16
MSB
31
En
Rn
General register ER
General register E
General register R
General register RH
General register RL
Most significant bit
Least significant bit
Legend
ERn:
En:
Rn:
RnH:
RnL:
MSB:
LSB:
0
MSB
LSB
15
Longword data
ERn
13