System register (sysreg) – NEC PD17062 User Manual
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PD17062
8. SYSTEM REGISTER (SYSREG)
“System register” is the generic name for those registers directly related to CPU control. System registers
are allocated at addresses 74H-7FH in data memory and can be referenced regardless of the bank specification.
The system register types are as follows:
Address register
Window register
Bank register
Memory pointer enable flag
Index register
Data memory row address pointer
General-purpose register pointer
Program status word
Fig. 8-1 Configuration of System Register
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
b
3
b
2
b
1
b
0
AR3
AR2
AR1
AR0
WR
BANK
IXH
IXM
MPH
MPL
IXL
RPH
RPL
PSW
74H
75H
76H
77H
78H
79H
7AH
7BH
7CH
7DH
7EH
7FH
0 0 0 0 0 0 0 0
0 0
P 0 0 0 0
0 0 0 0
B
C
D
C
M
P
C
Y
Z I
X
E
(IX)
Address
Register
Symbol
Bit
Data
Address register
(AR)
System register
Window
register
(WR)
Bank
register
(BANK)
Index register
(IX)
Data memory
row address
pointer
(MP)
General-
purpose
register
pointer
(RP)
Program
status
word
(PSWORD)
M
E
(MP)