H8S78 Datasheet, PDF (118/1208 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series

Section 2 CPU
2.5.2 Memory Data Formats
Figure 2.10 shows the data formats in memory. The H8S/2000 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 SP (ER7) is used as an address register to access the stack, the operand size should be word
size or longword size.
Data Type
1-bit data
Byte data
Address
Data Format
Address L
7
0
76 543210
Address L
MSB
LSB
Word data
Address 2M MSB
Address 2M+1
LSB
Longword data
Address 2N _MSB
Address 2N+1
Address 2N+2
Address 2N+3
LSB
Figure 2.10 Memory Data Formats
Rev.7.00 Mar. 18, 2009 page 50 of 1136
REJ09B0109-0700