hd66100 Renesas Electronics Corporation., hd66100 Datasheet - Page 34

• Manufacturer Part Number: hd66100
• Description: H8/3867 Series
• Manufacturer: Renesas Electronics Corporation.

2.3.2
Figure 2.4 indicates the data formats in memory. The H8/300L CPU can access word data stored
in memory (MOV.W instruction), but the word data must always begin at an even address. If word
data starting at an odd address is accessed, the least significant bit of the address is regarded as 0,
and the word data starting at the preceding address is accessed. The same applies to instruction
codes.
When the stack is accessed using R7 as an address register, word access should always be
performed. When the CCR is pushed on the stack, two identical copies of the CCR are pushed to
make a complete word. When they are restored, the lower byte is ignored.
Memory Data Formats
Byte data (CCR) on stack
CCR: Condition code register
Note:
Word data on stack
*
Ignored on return
Data Type
Word data
Byte data
1-bit data
Figure 2.4 Memory Data Formats
Even address
Even address
Even address
Odd address
Odd address
Odd address
Address
Address n
Address n
MSB
MSB
MSB
MSB
MSB
7
7
6
5
Data Format
Upper 8 bits
Lower 8 bits
4
CCR*
CCR
3
2
1
LSB
LSB
LSB
LSB
LSB
0
0
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