Samsung S3C9228/P9228, 8-Bit CMOS Microcontroller user manual Register Addressing Mode R

ADDRESSING MODES S3C9228/P9228

REGISTER ADDRESSING MODE (R)

In Register addressing mode, the operand is the content of a specified register (see Figure 3-1). Working register addressing differs from Register addressing because it uses a 16-byte working register space in the register file and a 4-bit register within that space (see Figure 3-2).

Program Memory

8-bit Register
File Address	dst
	OPCODE
One-Operand
Instruction
(Example)
Sample Instruction:

Register File

OPERAND Point to One

Rigister in Register

File

Value used in

Instruction Execution

DEC CNTR ; Where CNTR is the label of an 8-bit register address

Figure 3-1. Register Addressing

	Program Memory
4-Bit
Working Register
	dst	src
	OPCODE
Two-Operand
Instruction
(Example)

4 LSBs

Point to the

Woking Register

(1 of 16)

Register File

.

.

.

.

OPERAND

CFH

C0H

Sample Instruction:

ADD R1, R2 ; Where R1 = C1H and R2 = C2H

Figure 3-2. Working Register Addressing

3-2