VHDL-2008

Chapter 8. Standard Packages

In earlier versions of VHDL, the predefined types were declared in the package standard, specified in the VHDL Standard Language Reference Manual (LRM). Other standard types were specified in packages defined by separate IEEE standards. They included the packages math-real, math-complex, std_logic_1164, numeric_bit, and numeric_std. In VHDL-2008, all of these packages are included as part of the VHDL LRM, and so are now considered to be part of VHDL. VHDL also adds a number of new packages, including packages for fixed-point and floating-point numbers represented as vectors of std_ulogic elements, and a package providing access to the simulation environment. Furthermore, VHDL-2008 adds operations to the standard packages ...