S3C80A5B
ADDRESS SPACES
2-15
Together They Create an
8-bit Register Address
Register Pointer
Provides Five
High-order Bits
Address
OPCODE
Selects
RP0 or RP1
RP1
RP0
4-bit Address
Provides Three
Low-order Bits
Figure 2-11. 4-Bit Working Register Addressing
Register
Address
(76H)
RP0
0 1 1 1 0
0 0 0
0 1 1 1 0
1 1 0
R6
0 1 1 0
1 1 1 0
Selects RP0
Instruction:
'INC R6'
OPCODE
RP1
0 1 1 1 1
0 0 0
Figure 2-12. 4-Bit Working Register Addressing Example