1. Write the Control sequence for execution of the instruction SUB R1, 5(R2), R4 and microinstructions for

this instruction (Table), for single bus organization of the CPU, or SUB R15, (R22) 10 points)

STEP ACTION Comments 1 2 3 4 5 olol colla Internal processer bus Control signals PC Address Instruction decoder and control logic MAR Memory bus MDR Data lines IR RO Costa 4 Select MUX : Add B Sub R(-1) ALU or lines ALU . Carry-in XOR TEMP 2 Microinst. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 STEP ACTION Comments 1 2 3 4 5 olol colla Internal processer bus Control signals PC Address Instruction decoder and control logic MAR Memory bus MDR Data lines IR RO Costa 4 Select MUX : Add B Sub R(-1) ALU or lines ALU . Carry-in XOR TEMP 2 Microinst. 1 2 3 4 5 6 7 8 9 10 11 12 13 14