Question

Figure 4 shows a vertical microinstruction format and Table 2 shows the micro instruction field descriptions.

F1 F2 F3 CD BR AD F1, F2, F3: Microoperation fields CD: Condition for branching BR: Branch field AD: Address field Figure 4: Microinstruction Format Table 2: Microinstruction Field Descriptions F2 Microoperation F3 F1 Microoperation Microoperation 00 None 00 None 00 None 01 MARE PC 01 01 MARÇ (IR(Addr) IR (MBR) MBR Memory 10 PC PC + 1 10 10 AC0 11 PC MAR 11 MBR AC 11 IR(Addr) (MBR(Addr)) CD Comments BR Function 0 Unconditional branch 0 Jump Return/Map Conditional branch

Redraw the microinstruction format with the bit length of each fields shown in the drawing.

Answer 1

- 2 bits for fi microoperation = log2 4 = bits for Fz micro operations - by 2 4 = bits for F3 micro operations s lagar = 2 bits for condition for bron bronching for Bronen field = log 2² = 1 bits micro instruction format log 2² = bits Address vertical 6 F F2 F3 CD el BR AD 2 bit 2 bit 2 bit Ibit I bit 6 bit