Memory Data Formats - Renesas F-ZTAT H8 Series Hardware Manual

2.3.2

Memory Data Formats

Figure 2.4 indicates the data formats in memory. For access by the H8/300L CPU, word data
stored in memory must always begin at an even address. In word access the least significant bit of
the address is regarded as 0. If an odd address is specified, the access is performed at the preceding
even address. This rule affects the MOV.W instruction, and also applies to instruction fetching.
Byte data (CCR) on stack
Word data on stack
Legend:
CCR: Condition code register
Note: Ignored on return
*
When the stack is accessed using R7 as an address register, word access should always be
performed. For the CCR, the same value is stored in the upper 8 bits and lower 8 bits as word data.
On return, the lower 8 bits are ignored.
Data Type Address
1-bit data Address n
Byte data Address n
Even address
Word data
Odd address
Even address
Odd address
Even address
Odd address
Figure 2.4 Memory Data Formats
Data Format
7
7 6 5 4 3
MSB
MSB Upper 8 bits
Lower 8 bits
MSB CCR
MSB CCR*
MSB
Rev.3.00 Jul. 19, 2007 page 33 of 532
2. CPU
0
2 1 0
LSB
LSB
LSB
LSB
LSB
REJ09B0397-0300