Memory Data Formats - Hitachi H8/3035 Series Hardware Manual

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
1-bit data
Byte data
Word data
Longword data
When ER7 (SP) is used as an address register to access the stack, the operand size should be
word size or longword size.
26
Address
7
Address 7
Address
MSB
Address 2m
MSB
Address 2m + 1
Address 2n
MSB
Address 2n + 1
Address 2n + 2
Address 2n + 3
Figure 2-8 Memory Data Formats
Data Format
6 5 4 3 2 1
0
0
LSB
LSB
LSB