CM71-00105-1E FUJITSU MICROELECTRONICS LIMITED 13
FR81 Family CHAPTER 2 MEMORY ARCHITECTURE
2.2
2.2.4 Byte Order
The byte order of FR81 Family CPU is big endian. When word data or half word data are allocated to
address spaces, the higher bytes are placed in the lower address side while the lower bytes are placed in the
higher address side. The arrangement of big endian byte data is shown in Figure 2.2-4.
For example, if a word data was written on the memory (RAM) at address location 0004 1234H of the
memory space, the highest byte will be stored at location 0004 1234H while the lowest byte will be stored
at location byte 0004 1237H.
Figure 2.2-4 Big Endian Byte Orde
MSB Higher byte Lower byte LSB
Address Address +1
Half word
MSB
Higher half word Lower half word
LSB
Highest byte Lowest byte
Address Address +1 Address +2 Address +3
Word
MSB
Byte Address
LSB