Question

I am working on a project but whatever I do I can’t understand what this code does. Since I am not familiar with VHDL, it’s really hard for me to understand the purpose of this code.

library iee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use work.my_package.all;

Entity multiplier is

    generic (size: integer :=4);
    Port (a,b : in unsigned( size-1 downto 0);
        y : out unsigned( size-1 downto 0));

End multiplier ;

ARCHITECTURE behavior of multiplier is

Begin

    y<= mult(a,b);

End behavior;

Answer 1

You have an entity which describes the interface of your design. In this case inputs a and b as well as output y. These are all 4-bit values.

The architecture contains the implementation of what you’re trying to do (the body if you will). In this case it’s simply a multiplication of a and b, which is assigned to y. And (should you be confused) no, the <= does not stand for “smaller than or equal to” but it’s an assignment.