RL78/G1P
CHAPTER 3 CPU ARCHITECTURE
R01UH0895EJ0100 Rev.1.00
38
Nov 29, 2019
3.2.3 ES and CS registers
The ES register and CS register are used to specify the higher address for data access and when a branch instruction
is executed (register indirect addressing), respectively.
The default value of the ES register after reset is 0FH, and that of the CS register is 00H.
Figure 3-8. Configuration of ES and CS Registers
0
0
0
0
ES3
ES2
ES1
ES0
7
0
ES
6
5
4
3
2
1
0
0
0
0
CS3
CP2
CP1
CP0
7
0
CS
6
5
4
3
2
1
Though the data area which can be accessed with 16-bit addresses is the 64 Kbytes from F0000H to FFFFFH, using the
ES register as well extends this to the 1 Mbyte from 00000H to FFFFFH.
Figure 3-9. Extension of Data Area Which Can Be Accessed
Special function register
(SFR) 256 bytes
Extended special function register
(2nd SFR) 2 Kbytes
FFFFFH
00000H
Code flash memory
F0000H
EFFFFH
Data memory space
!saddr16
ES:!saddr16
ES:!saddr16
!saddr16
0H - FH
0000H - FFFFH
0000H - FFFFH
F