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CHAPTER 2 MEMORY ARCHITECTURE
2.2
Bit Order and Byte Order
This section describes the order in which three types of data, 8, 16, and 32 bits, are
placed in memory in the FR family.
In the FR family, the bit number increases approaching the MSB, and the byte number
increases approaching the lowest address value.
■ Bit Order and Byte Order
Bit order in the general-purpose register is that the larger numbers are placed in the vicinity of MSB while
the smaller numbers are in the LSB. Byte order configuration requires the upper data to be placed in the
smaller address memory, while the lower data are placed in the larger address memory.
Figure 2.2-1illustrates the bit order and byte order in the FR family.
0000 0000
1234 5678
1234 5679
1234 567A
1234 567B
FFFF FFFF
10
Figure 2.2-1 Bit Order and Byte Order
Bit order
Memory space
H
12
H
H
34
H
H
56
H
H
78
H
H
H
31
2423
1615
R0
12
34
56
H
H
R10 12345678
H
8 7
0
78
H
H
LD @R10,R0
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