S3C80A5B
ADDRESS SPACES
2-13
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.
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
FFH
C0H
BFH
Set 2
00H
Prime
Area
Set 1
FFH
CFH
C0H
FCH
E0H
DFH
Page 0
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Figure 2-10. Common Working Register Area