Write a code in VHDL for a $4-$bit ALU with the external interface as shown in the following figure, Where:

Inputs are:

o Two $4-$bit two's complement operands $($A $,$ B$)$

o A $3-$bit control signal $($Op$)$

$$ Outputs are:

o A $4-$bit two's complement result $($R$)$

o Z status flag $($set when ALU result is zero$)$

o N status flag $($set when ALU result is negative$)$

o Overflow flag $($set when ALU result is wrong$)$

The ALU's supported operations table is:

Op$2$ Op$1$ Op$0$ R Operation

$0000$ clear

$001$ A $+$ B add$/$subtract

$010$ B $+1$ Increment

$011$ A $|$ B or

$101$ A & B and

$110$ ~ B bitwise complement

$111$ A transfer