new integer types: systemverilog defines codice_8, codice_9, codice_10 and codice_11 as two-state signed integral types having 8, 16, 32, and 64 bits respectively. a codice_12 type is a variable-width two-state type that works much like codice_13. two-state types lack the x and z metavalues of classical verilog; working with these types may result in faster simulation.