Indexed (X) Addressing Mode (Concluded) - Samsung S3F84B8 User Manual

S3F84B8_UM_REV 1.00

3.9 INDEXED (X) ADDRESSING MODE (CONCLUDED)

4-bit Working
Register Address
Sample Instructions:
LDC
LDE
Program Memory
OFFSET
OFFSET
dst/src src
OPCODE
8-Bits
R4, #1000H[RR2]
R4,#1000H[RR2]
Figure 3-9 Indexed Addressing to Program or Data Memory
MSB Points to
RP0 or RP1
~
NEXT 2 Bits
Point to Working
Register Pair
Program Memory
LSB Selects
+
16-Bits
16-Bits
; The values in the program address (RR2 + 1000H)
are loaded into register R4.
; Identical operation to LDC example, except that
external program memory is accessed.
3-9
3 ADDRESSING MODES
Register File
RP0 or RP1
Selected
RP points
to start of
~
working
register
block
Register
Pair
or
Data Memory
Value used in
OPERAND
Instruction
16-Bit
address
added to
offset