handel-c
- A variant of C, handel-c is a behavioral language for FPGA design.
- http://www.celoxica.com/

bluespec
- Bluespec adds extensions on to System Verilog to raise the abstraction level for complex control logic.
- http://www.bluespec.com/

AHDL
- Altera's HDL.
- http://www.altera.com/support/examples/ahdl/ahdl.html