RL78/G1H CHAPTER 4 CPU ARCHITECTURE
R01UH0575EJ0120 Rev. 1.20 Page 52 of 920
Dec 22, 2016
4.2.3 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 direct addressing), respectively.
The default value of the ES register after reset is 0FH, and that of the CS register is 00H.
Figure 4 - 10 Configuration of ES and CS Registers
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 4 - 11 Extension of Data Area Which Can Be Accessed
76543210
ES 0 0 0 0 ES3 ES2 ES1 ES0
76543210
CS 0 0 0 0 CS3 CS2 CS1 CS0
Special function register
(SFR) 256 bytes
Extended special function register
(2nd SFR) 2 Kbytes
FFFFFH
00000H
Code flash memory
F0000H
EFFFFH
Data memory space
!addr16
!addr16
→ F 0000H - FFFFH
→
0H - FH 0000H - FFFFH
ES:!addr16
ES:!addr16
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