Hello, I'm learning an opensource cad tool called alliance , it takes a vhdl design and turns it into a wafer digital layout , its VHDL compiler is called SYF , the problem is that a code that compiled successfully on modelsim won't compile here , my VHDL is not very strong so I hope someone could give my an explanation : the problem is with variable declaration process(CS,wordin,reset) variable addr : std_logic_vector (7 DOWNTO 0); begin ... error : ILLEGAL DECLARATION at the variable declaration line any help ?