S3C825A Datasheet, PDF (58/346 Pages) Samsung semiconductor – 8-BIT CMOS MICROCONTROLLERS

ADDRESSING MODES
INDIRECT REGISTER ADDRESSING MODE (Concluded)
S3C825A/P825A
MSB Points to
RP0 or RP1
Register File
RP0 or RP1
4-bit Working
Register Address
Example Instruction
References either
Program Memory or
Data Memory
Program Memory
dst
src
OPCODE
Next 2-bit Point
to Working
Register Pair
(1 of 4)
LSB Selects
Register
Pair
Program Memory
or
Data Memory
Value used in
Instruction
OPERAND
Selected
RP points
to start of
working
register
block
16-Bit
address
points to
program
memory
or data
memory
Sample Instructions:
LDC
LDE
LDE
R5,@RR6
R3,@RR14
@RR4, R8
; Program memory access
; External data memory access
; External data memory access
Figure 3-6. Indirect Working Register Addressing to Program or Data Memory
3-6