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

S3F84B8_UM_REV 1.00

3.8 INDEXED (X) ADDRESSING MODE (CONTINUED)

4-bit Working
Register Address
Sample Instructions:
LDC
LDE
Figure 3-8
Program Memory
OFFSET
dst/src x
OPCODE
LSB Selects
8-Bits
R4, #04H[RR2]
R4, #04H[RR2]
Indexed Addressing to Program or Data Memory with Short Offset
Register File
MSB Points to
RP0 or RP1
RP0 or RP1
~
NEXT 2 Bits
Point to Working
Register Pair
(1 of 4)
Program Memory
Data Memory
+
16-Bits
16-Bits
; The values in the program address (RR2 + 04H)
are loaded into register R4.
; Identical operation to LDC example, except that
external program memory is accessed.
3-8
3 ADDRESSING MODES
Selected
RP points
to start of
~
working
register
block
Register
Pair
16-Bit
address
added to
offset
or
Value used in
OPERAND
Instruction