S3P80C5/C80C5/C80C8
COMMON WORKING REGISTER AREA (C0H–CFH)
After a reset, register pointers RP0 and RP1 automatically select two 8-byte register slices in set 1, locations
C0H–CFH, as the active 16-byte working register block:
RP0 → C0H–C7H
RP1 → C8H–CFH
This 16-byte address range is called common area. That is, locations in this area can be used as working
registers by operations that address any location on any page in the register file. Typically, these working
registers serve as temporary buffers for data operations between different pages.
FFH
FCH
E0H
DFH
CFH
C0H
Register a hardware reset, register
pointers RP0 and RP1 point to the
commom working register area,
locations C0H-CfH.
RP0 =
1 1 0 0
0 0 0 0
RP1 =
1 1 0 0
1 0 0 0
Figure 2-10. Common Working Register Area
Page 0
Set 1
FFH
C0H
BFH
~
00H
ADDRESS SPACES
Set 2
Prime
~
Area
2-13