Samsung S3F80JB manual Indirect Register Addressing Mode IR

S3F80JB 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, if implemented (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. Remember, however, that locations C0H–FFH in set 1 cannot be accessed using Indirect Register addressing mode.

	Program Memory
8-bit register
file address
	dst
	OPCODE
One-Operand
Instruction
(Example)

Points to one

register in register

file

Address of operand used by instruction

Register File

ADDRESS

Value used in instruction execution

Sample Instruction:

OPERAND

RL @SHIFT ; Where SHIFT is the label of an 8-bit register address.

Figure 3-3. Indirect Register Addressing to Register File

3-3