Register Addressing mode - computer architecture:
Register addressing mode is same to direct addressing. Only difference in between is that the address field of the instruction refers to a register rather than a memory location three or four bits are used as address field to refer once 8 to 16 produced purpose registers. The benefit of register addressing are little address field is required in the instruction.
Register Indirect Addressing:
This mode is same to indirect addressing. Address field of this instruction refers to a register. The register contains the valuable address of the operand. This mode uses one memory reference to get the operand. The address space is restricted to the width of the registers available to store the effective address.