Renesas Hitachi H8S/2191, Hardware Manual, Page: 57 / 1065

Rev. 2.0, 11/00, page 30 of 1037
2.5.2 Memory Data Formats
Figure 2.11 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.
7 0
7 6 5 4 3 2 1 0
MSB
LSB
MSB
MSB
LSB
LSB
Address
Address L
Address L
Address 2M
Address 2N
Address 2N+1
Address 2N+2
Address 2N+3
1-bit data
Byte data
Word data
Longword data
Data Type
Data Format
Address 2M+1
Figure 2.11 Memory Data Formats
When ER7 (SP) is used as an address register to access the stack, the operand size should be
word size or longword size.