RX610 Group
2. CPU
R01UH0032EJ0120 Rev.1.20
Page 73 of 1006
Feb 20, 2013
2.5.4
Data Arrangement
2.5.4.1
Data Arrangement in Registers
Figure 2.6 shows the relation between the sizes of registers and bit numbers.
Longword (32-bit) data
b31
b0
b15
b0
b7
b0
Word (16-bit) data
Byte (8-bit) data
MSB
LSB
Figure 2.6 Data Arrangement in Registers
2.5.4.2
Data Arrangement in Memory
Data in memory have three sizes: byte (8-bit), word (16-bit), and longword (32-bit). The data arrangement is selectable as
little endian or big endian. Figure 2.7 shows the arrangement of data in memory.
1-bit data
(Little endian)
(Big endian)
Address L
Address L
Byte data
Word data
Address M
Address M+1
Address N
Address N+1
Address N+2
Address N+3
Longword data
Data image
Data type
b7
b0
LSB
MSB
Data image
Address
7
6
5
4
3
2
1
0
LSB
LSB
MSB
MSB
b7
b0
LSB
MSB
7
6
5
4
3
2
1
0
LSB
LSB
MSB
MSB
Figure 2.7 Data Arrangement in Memory
2.5.5
Notes on Arrangement of Instruction Code
When the endian setting for the external address space is different from that for the chip, no instruction code can be
arranged in the area. The instruction code should be arranged in the external address space whose endian setting is the
same as that for the chip