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2 bit order and byte order, Bit order and byte order – FUJITSU FR family 32-bit microcontroller instruction manuel CM71-00101-5E User Manual

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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 the 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 the MSB

while the smaller numbers are near 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 2.2-1 illustrates the bit order and byte order in the FR family.

Figure 2.2-1 Bit Order and Byte Order

Bit order

Memory

s

p

a

ce

12

H

3

4

H

56

H

7

8

H

0000 0000

H

12

3

4 567

8

H

12

3

4 5679

H

12

3

4 567A

H

12

3

4 567B

H

FFFF FFFF

H

R10 12

3

4567

8

H

LD @R10,R0

3

1

242

3

1615

8

7

0

R0

12

H

3

4

H

56

H

7

8

H