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RL78/G1A CHAPTER 3 CPU ARCHITECTURE
R01UH0305EJ0200 Rev.2.00 65
Jul 04, 2013
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 direct addressing), respectively.
The default value of the ES register after reset is 0FH, and that of the CS register is 00H.
Figure 3-11. Configuration of ES and CS Registers
0 0 0 0 ES3 ES2 ES1 ES0
70
ES
6
5
4
3
21
0 0 0 0 CS3 CS2 CS1 CS0
70
CS
6
5
4
3
21
Though the data area which can be accessed with 16-bit addresses is the 64 KB from F0000H to FFFFFH, using the
ES register as well extends this to the 1 MB from 00000H to FFFFFH.
Figure 3-12. Extension of Data Area Which Can Be Accessed
Special function register
(SFR) 256 bytes
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
<R>
<R>