ADDRESS SPACES
S3C8639/C863A/P863A/C8647/F8647
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
This16-byte address range is called common working register 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
Set 1
Page 0
Page 1
Page 2
Page 3 (S3C863A only)
FFH
FFH
Set 2
Set 2 Set 2 Set 2
C0H
C0H
BFH
BFH
Register pointers RP0 and RP1 point to the
common working register area, locations
C0H-CFH, after a reset.
RP0 = 1 1 0 0 0 0 0 0
~
Prime
Area
~
~~
Prime
Area
~~
Prime Prime
Area Area
RP1 = 1 1 0 0 1 0 0 0
00H
00H
Figure 2-12. Common Working Register Area (S3C863X)
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