Thanks for your quick response(again).You are right that i think most like vhdl is a programming language because i am a newbie in vhdl.But from the things you wrote you mean that what i want to do is difficult?The first step as far as i know is a simple MAC unit.The difficult part is the part that i have to adjust the weights in order for sum>threshold.Can you please tell me at least if the first part(the MAC unit) is correct?As i mentioned above i want to insert 3 inputs,each of one has a weight and then multiply each input with each weight and finally sum.Thanks again.