Please help me design keypad interface which makes data and control signal using verilog.(this circuit will be used for digital calculator project). Data should use 2's complement and range of BCD # is from-9999 to 99999

1)Design the circuit convert BCD into binary code and save at register. If input range is over 99999 or less than -9999, then set overflow on D FF or reset.

2)

2)Operator

AC: 10

Sign +/- :11/12

/(divider):13

*(multiplier):14

-(subtractor):15

+(adder):16

=(return):17 in BCD, and module should delete MSB and save in 4-bit D-FF register