Samsung S3C8275X - Manual (Page 65)

S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X ADDRESSING MODES
3-9
INDEXED ADDRESSING MODE (Concluded)
Register File
OPERAND
Program Memory
or
Data Memory
Point to Working
Register Pair
LSB Selects
16-Bit
address
added to
offset
RP0 or RP1
MSB Points to
RP0 or RP1
Selected
RP points
to start of
working
register
block
Sample Instructions:
LDC R4, #1000H[RR2] ; The values in the program address (RR2 + 1000H)
are loaded into register R4.
LDE R4,#1000H[RR2] ; Identical operation to LDC example, except that
external program memory is accessed.
NEXT 2 Bits
Register
Pair
Value used in
Instruction
8-Bits 16-Bits
16-Bits
dst/src
OPCODE
Program Memory
src
OFFSET
4-bit Working
Register Address
OFFSET
+
~ ~
Figure 3-9. Indexed Addressing to Program or Data Memory