Samsung S3C9228/P9228, 8-Bit CMOS Microcontroller Indirect Register Addressing Mode Concluded

ADDRESSING MODES S3C9228/P9228

INDIRECT REGISTER ADDRESSING MODE (Concluded)

Program Memory

4-Bit Working

Register Address

dst src

OPCODE

Example Instruction References either Program Memory or Data Memory

Next 3 Bits Point

to Working

Register Pair

(1 of 8)

LSB Selects

Value used in Instruction

Register File

.

.

.

.

Register

Pair

Program Memory

or

Data Memory

OPERAND

CFH

C0H

16-Bit address points to program memory or data memory

Sample Instructions:
LCD	R5,@RR6	;	Program memory access
LDE	R3,@RR14	; External data memory access
LDE	@RR4, R8	;	External data memory access

Figure 3-6. Indirect Working Register Addressing to Program or Data Memory

3-6