[2 marks] (b) In the CISC system shown in figure Q4 with the instruction set given in table Q4(a) executes SWB (Subtract With Borrow) instruction. This instruction is defined as follows: RDRY - RSA - RSB-B Borrow B is defined as the complement of the carry out, C. Write and describe the microinstructions that are required to execute this instruction by filling the table below. Use Table Q4(b) if necessary. (10 marks) Action Address MZ CA RW DX MD FS MA MB AX BX CS [2 marks] (b) In the CISC system shown in figure Q4 with the instruction set given in table Q4(a) executes SWB (Subtract With Borrow) instruction. This instruction is defined as follows: RDRY - RSA - RSB-B Borrow B is defined as the complement of the carry out, C. Write and describe the microinstructions that are required to execute this instruction by filling the table below. Use Table Q4(b) if necessary. (10 marks) Action Address MZ CA RW DX MD FS MA MB AX BX CS