Samsung S3F80JB manual Register Addressing Mode R

ADDRESSING MODES S3F80JB

REGISTER ADDRESSING MODE (R)

In Register addressing mode, the operand is the content of a specified register or register pair (see Figure 3-1). Working register addressing differs from Register addressing because it uses a register pointer to specify an 8- byte working register space in the register file and an 8-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 Points to one

register 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)	Sample Instruction:

MSB Points to

RP0 ot RP1

3 LSBs

Points to the

woking register

(1 of 8)

Register File

RP0 or RP1

OPERAND

Selected RP points

to start

of working register block

ADD	R1, R2	; Where R1 and R2 are registers in the curruntly
		selected working register area.

Figure 3-2. Working Register Addressing

3-2