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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.
Rev. 3.00 Jan 25, 2006 page 32 of 872
REJ09B0286-0300
Data Type
Address
1-bit data
Address L
Byte data
Address L
Word data
Address 2M
Address 2M + 1
Longword data
Address 2N
Address 2N + 1
Address 2N + 2
Address 2N + 3
Figure 2.10 Memory Data Formats
Data Image
7
7
6
5
4
3
2
1
MSB
LSB
MSB
LSB
MSB
LSB
0
0
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