Memory Data Formats - Renesas H8S Series Hardware Manual

2.5.2

Memory Data Formats

Figure 2-8 shows the data formats in memory. The CPU can access word data and longword data in 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.
When ER7 is used as an address register to access the stack, the operand size should be word size or longword size.
Rev.6.00 Oct.28.2004 page 32 of 1016
REJ09B0138-0600H
Data Type
1-bit data
Byte data
Word data
Address 2M + 1
Longword data
Figure 2-8 Memory Data Formats
Address
7
Address L 7 6
Address L MSB
Address 2M MSB
Address 2N
MSB
Address 2N + 1
Address 2N + 2
Address 2N + 3
Data Format
0
5 4 3 2 1 0
LSB
LSB
LSB