Common Working Register Area (C0H–Cfh) - Samsung S3F84B8 User Manual

S3F84B8_UM_REV 1.00
2.4.1 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. The locations in this area can be used as working registers for
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.
Following a hardware reset, register
pointers RP0 and RP1 point to the
common working register area,
locations C0H-CFH.
RP0 =
RP1 =
As shown in the following examples, you should access working registers in the common area (locations C0H–
CFH) using working register addressing mode only.
1. LD
Use working register addressing instead:
SRP
LD
2. ADD 0C3H, #45H
Use working register addressing instead:
SRP
ADD
Set 1
FFH
FCH
E0H
D0H
C0H
1 1 0 0 0 0 0 0
1 1 0 0 1 0 0 0
Figure 2-11
Example 2-3 Addressing the Common Working Register Area
0C2H, 40H
#0C0H
R2, 40H
#0C0H
R3, #45H
FFH
FFH
Page 0
Set 2
C0H
BFH
Page 0
Prime
~
Space
00H
Common Working Register Area
; Invalid addressing mode
; R2 (C2H)  the value in location 40H
; Invalid addressing mode
; R3 (C3H)  R3 + 45H
2-14
2 ADDRESS SPACES
Page 1
Set 2
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