Assume that the following changes are made in the basic computer: The hardwired control unit is replaced by the microprogrammed control unit; The size of control memory is $12820.$ There are two registers SBR and CAR available in the control unit; A microprogram can use eight consecutive memory locations in the control memory. The microinstruction is of $20$ bits and contains the following fields:

$\backslash$table$[[$F$1,$F$2,$F$3,$CD$,$BR$,$AD$],[(3$ bits$),(3$ bits$),(3$ bits$),(2$ bits$),(2$ bits$),(7$ bits$)]]$

a$)$ Formulate the correct mapping procedure for this computer

b$)$ Give the symbolic microprogram for the following instructions of the basic computer:

ADD $($Opcode : $100)$ : AClarrAC$+M[EA]$

BRANCH $($Opcode : $101)$ : If $)<mi\; id="EditorElement\_710073">(</mi><mn\; id="EditorElement\_710067">0</mn>$ then PClarrEA

c$)$ Specify the symbolic routines for Fetching the instruction and