Verilog ALU that multiplies using asterix

Hello!

I have a project that can do;

It accomplishes all of this perfectly. Now I need to edit the program in a way that it multiplies 2 numbers instead of add them. I need to do this with arithmetic operator which is * symbol (verilog accepts it as I was told by my instructor) However I got stuck because my ALU doesn't use arithmetic operator so its not as simple as changing operator (it was not what i was told ) What I am trying to accomplish is that, I don't the program to add anymore, just multiply. For that All I need to change is the ALU that multiples 2 numbers (just like adding 2 numbers which my project does atm) However, wherever I checked, I couldn't find any trace of this.
this is what my ALU looks like now.





I am sure this is not even that difficult for those who are really familiar with Verilog programming however there is just little information on internet and my book about this thing I am trying to accomplish, which is converting ALU into multiplier instead of adder using asterisk. This is the schematic of my project;




Let me know if you have a question about it.

Thanks in advance.

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Here is my project as zipped, if anyone would like to see it. (Note it requires, spartan 3e FPGA board, VGA screen and a keyboard with pinned end to see the output of the bit file) I have those tools available to test the bit file.