Comparing CλaSH and VHDL by implementing a dataflow processor

As embedded systems are becoming increasingly complex, the design process and verification have become very time-consuming. Additionally, specifying hardware manually in a low-level hardware description language like VHDL is usually an error-prone task. In our group, a tool (the CλaSH compiler) was developed to generate fully synthesisable VHDL code from a specification given in the functional programming language Haskell. In this paper, we present a comparison between two implementations of the same design by using CλaSH and handwritten VHDL. The design is a simple dataflow processor. As measures of interest area, performance, power consumption and source lines of code (SLOC) are used. The obtained results indicate that the CλaSH-generated VHDL code as well as the netlist after synthesis and place and route are functionally correct. The placed and routed hand-written VHDL code has also the correct behaviour. Furthermore, a similar performance is achieved. The power consumption is even lower for the CλaSH implementation. The SLOC for CλaSH is considerably smaller and it is possible to specify the design in a much higher level of abstraction compared to VHDL.