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

S3C9228/P9228 ADDRESSING MODES

INDIRECT REGISTER ADDRESSING MODE (IR)

In Indirect Register (IR) addressing mode, the content of the specified register or register pair is the address of the operand. Depending on the instruction used, the actual address may point to a register in the register file, to program memory (ROM), or to an external memory space (see Figures 3-3 through 3-6).

You can use any 8-bit register to indirectly address another register. Any 16-bit register pair can be used to indirectly address another memory location.

		Program Memory				Register File
8-Bit Register
File Address
			dst			ADDRESS
					Point to One
		OPCODE
					Rigister in Register
One-Operand
					File
Instruction
					Address of Operand
(Example)
					used by Instruction
					Value used in	OPERAND
				Instruction Execution
Sample Instruction:
RL	@SHIFT		;	Where SHIFT is the label of an 8-Bit register address

Figure 3-3. Indirect Register Addressing to Register File

3-3