Datasheet

Section 2 CPU
Rev. 6.00 Aug 04, 2006 page 46 of 680
REJ09B0145-0600
2.3.2 Memory Data Formats
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.
Data Format
76543210
AddressData Type
70
Address n
MSB LSB
MSB
LSB
Upper 8 bits
Lower 8 bits
MSB LSBCCR
CCR*
MSB
LSB
MSB LSB
Address n
Even address
Odd address
Even address
Odd address
Even address
Odd address
1-bit data
Byte data
Word data
Byte data (CCR) on stack
Word data on stack
CCR: Condition code register
Note: I
g
nored on return*
Figure 2.4 Memory Data Formats
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.