C to HDL

C to HDLtools convertC languageorC-likecomputer codeinto ahardware description language(HDL) such asVHDLorVerilog.The converted code can then besynthesizedandtranslatedinto a hardware device such as afield-programmable gate array.Compared tosoftware,equivalent designs inhardwareconsume less power (yielding higherperformance per watt) and execute faster with lowerlatency,moreparallelismand higherthroughput.However,system designandfunctional verificationin a hardware description language can be tedious and time-consuming, so systems engineers often writecritical modulesin HDL and othermodulesin ahigh-level languageand synthesize these into HDL through C to HDL orhigh-level synthesistools.

C toRTLis another name for this methodology. RTL refers to theregister transfer levelrepresentation of a program necessary to implement it in logic.

History

Early development on C to HDL was done by Ian Page, Charles Sweeney and colleagues atOxford Universityin the 1990s who developed theHandel-Clanguage. Theycommercializedtheir research by forming Embedded Solutions Limited (ESL) in 1999 which was renamed Celoxica in September 2000. In 2008, the embedded systems departments of Celoxica was sold to Catalytic for $3 million and which later merged to become Agility Computing.In January 2009,Mentor Graphicsacquired Agility's C synthesis assets.Celoxica continues to trade concentrating onhardware accelerationto process transactions in the financial sector and otherindustries.

Applications

C to HDL techniques are most commonly applied toapplicationsthat have unacceptably highexecution timeson existing general-purposesupercomputerarchitectures. Examples includebioinformatics,computational fluid dynamics(CFD),financial processing, and oil and gas survey data analysis.Embedded applicationsrequiringhigh performanceorreal-timedata processingare also an area of use.System-on-chip(SoC) design may also take advantage of C to HDL techniques.

C-to-VHDL compilers are very useful for large designs or for implementing code that might change in the future. Designing a large application entirely in HDL may be very difficult and time-consuming; the abstraction of a high level language for such a large application will often reduce total development time. Furthermore, an application coded in HDL will almost certainly be more difficult to modify than one coded in a higher level language. If the designer needs to add new functionality to the application, adding a few lines of C code will almost always be easier than remodeling the equivalent HDL code.

Flow to HDLtools have a similar aim, but withflowrather than C-based design.

Example tools

• SmartHLS(originally LegUp), ANSI C to Verilog tool developed byMicrochip Technology,based on LLVM compiler.
• CBG CtoVA tool developed 1995-99 by DJ Greaves (University of Cambridge) that instantiated RAMs and interpreted variousSystemCconstructs and datatypes.
• C-to-Verilog tool (NISC) fromUniversity of California, Irvine
• Altium Designer 6.9 and 7.0(a.k.a. Summer 08) fromAltium
• Nios II C-to-Hardware Acceleration CompilerfromAltera
• Catapult Ctool fromMentor Graphics
• Cynthesizer fromForte Design Systems
• SystemCfromCeloxica (defunct)
• Handel-CfromCeloxica (defunct)
• DIME-CfromNallatech
• Impulse CfromImpulse Accelerated Technologies
• FpgaCwhich is an open source initiative
• SA-C programming language
• Cascade (C to RTL synthesizer) fromCriticalBlue
• Mitrion-CfromMitrionics
• SPARK (a C-to-VHDL) fromUniversity of California, San Diego
• VLSI/VHDL CAD Group Index of Useful Tools fromCase Western Reserve University
• MyHDLis a Python-subset compiler and simulator toVHDLandVerilog

See also

• Comparison of EDA Software
• Electronic design automation(EDA)
• High-level synthesis
• Silicon compiler
• Hardware acceleration

External links

• A good article on Dr Dobbs Journal about ImpulseC.
• An overview of flows by Daresbury Labs.
• An Overview of Hardware Compilation and the Handel-C language.
• Xilinx's ESL initiative, some products listed and C to VHDL tools.
• Altium's C-to-Hardware Compiler overview.
• Altera's Nios II C2H Acceleration Compiler White Paper.