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S3C80A5B
INDEXED ADDRESSING MODE (Continued)
4 Bit Working
Register Address
Sample Instructions:
LDC
LDE
NOTE: LDE command is not available, because an external interface is not implemented for
Program Memory
OFFSET
OFFSET
dst/src
x
OPCODE
R4, #1000H[RR2] ; The values in the program address (RR2 + 1000H)
R4, #1000H[RR2] ; Identical operation to LDC example, except that
the S3C80A5B.
Figure 3-9. Indexed Addressing to Program or Data Memory
MSB Points to
RP0 or RP1
~
Next 2 Bits
Point to Working
Register Pair
LSB Selects
+
16-Bits
8-Bits
16-Bits
are loaded into register R4.
external program memory is accessed.
ADDRESSING MODES
Register File
RP0 or RP1
~
Register
Pair
Program Memory
or
Data Memory
Value used in
OPERAND
Instruction
Selected
RP Points
to Start of
Working
Register
Block
16 Bit
Address
Added to
Offset
3-9
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