sentences:  As design shifted to VLSI, the first modern HDL, Verilog, was introduced by Gateway Design Automation in 1985.Cadence Design Systems later acquired the rights to Verilog-XL, the HDL simulator that would become the de facto standard of Verilog simulators for the next decade.In 1987, a request from the U.S. Department of Defense led to the development of VHDL (VHSIC Hardware Description Language).