Accumulator (Acc); Index Register X (X); Index Register Y (Y); Stack Pointer (S) - Renesas 7700 FAMILY User Manual

CENTRAL PROCESSING UNIT (CPU)
2.1 Central processing unit
2.1 Central processing unit
The CPU (Central Processing Unit) has the ten registers as shown in Figure 2.1.1.
b7
DT
b23
PG
b7
b15
0 0 0 0
Fig. 2.1.1 CPU registers structure
2–2
b15
A
H
b15
B
H
b15
X
H
b15
Y
H
b15
S
H
b0
b16 b15
PC
H
b0
b15
DPR
H
b15
PS
H
b10 b9 b8 b7 b6
0 IPL N V
7751 Group User's Manual
b0
b8 b7
A
L
b0
b8 b7
B
L
b0
b8 b7
X
L
b0
b8 b7
Y
L
b0
b8 b7
S
L
b8 b7
b0
PC
L
b0
b8 b7
DPR
L
b0
b8 b7
PS
L
b5 b4 b3 b2 b1 b0
m x D I Z C
Index register length flag
Data length flag
Overflow flag
Negative flag
Processor interrupt priority level
Accumulator A (A)
Accumulator B (B)

Index register X (X)

Index register Y (Y)

Stack pointer (S)

Data bank register (DT)
Program counter (PC)
Program bank register (PG)
Direct page register (DPR)
Processor status register (PS)
Carry flag
Zero flag
Interrupt disable flag
Decimal mode flag