clash-lib - CλaSH compiler, as a library

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CλaSH - A functional hardware description language

CλaSH (pronounced ‘clash’) is a functional hardware description language that borrows both its syntax and semantics from the functional programming language Haskell. The CλaSH compiler transforms these high-level descriptions to low-level synthesizable VHDL, Verilog, or SystemVerilog.

Features of CλaSH:

  • Strongly typed (like VHDL), yet with a very high degree of type inference, enabling both safe and fast prototying using consise descriptions (like Verilog).

  • Interactive REPL: load your designs in an interpreter and easily test all your component without needing to setup a test bench.

  • Higher-order functions, with type inference, result in designs that are fully parametric by default.

  • Synchronous sequential circuit design based on streams of values, called Signals, lead to natural descriptions of feedback loops.

  • Support for multiple clock domains, with type safe clock domain crossing.

Support

For updates and questions join the mailing list [email protected] or read the forum

Changes

Changelog for the clash-lib package

0.99.3 July 28th 2018

  • Fixes bugs:
    • Evaluator recognizes Bit literals #329
    • Use existential type-variables in context of GADT pattern match
    • Do not create zero-bit temporary variables in generated HDL
    • Use correct arguments in nested primitives #323
    • Zero-constructor data type needs 0 bits #238
    • Create empty component when result needs 0 bits
    • Evaluator performs BigNat arithmetic

0.99.1 May 12th 2018

  • Allow ~NAME[N] tag inside ~GENSYM[X]
  • Support HDL record selector generation #313

0.99 March 31st 2018

  • New features:
    • Support for clash-prelude-0.99:
      • Explicit clock and reset arguments
      • Overhaul of TopEntity annotations
    • Hierarchies with multiple synthesisable boundaries by allowing more than one function in scope to have a Synthesize annotation.
      • Local caching of functions with a Synthesize annotation
    • Bit type is mapped to a HDL scalar type (e.g. std_logic in VHDL)
    • Improved name preservation
    • Zero-bit values are filtered out of the generated HDL
    • Improved compile-time computation
  • Many bug fixes

0.7.1 April 11th 2017

  • New features:
    • Support distribution of primitive templates with Cabal/Hackage packages commit
    • Find memory data files and primitive files relative to import dirs (-i<DIR>)
  • Fixes bugs:
    • case (EmptyCase ty) of ty' { ... } -> EmptyCase ty' #198
    • BitVector.split# apply the correct type arguments

0.7 January 16th 2017

  • New features:
    • Support for clash-prelude 0.11
    • Primitive templates can include QSys files
    • VHDL blackboxes: support additional libraries and uses keywords in generated VHDL
    • Highly limited Float/Double support (literals and Rational conversion), hidden behind the -clash-float-support flag.
  • Fixes bugs:
    • Reduce type families inside clock period calculation #180
    • Only output signed literals as hex when they’re multiple of 4 bits #187
    • Correctly print negative hex literals

0.6.21 August 18th 2016

  • Fixes bugs:
    • Type families are not currently being reduced correctly #167

0.6.20 August 3rd 2016

  • Fixes bugs:
    • Bug in DEC transformation overwrites case-alternatives
    • Bug in DEC transformation creates non-representable let-binders

0.6.19 July 19th 2016

  • Fixes bugs:
    • Rounding error in logBase calculation

0.6.18 July 15th 2016

  • New features:
    • Better error location reporting
  • Fixes bugs:
    • Values of type Index ‘n’, where ‘n’ > 2^MACHINE_WIDTH, incorrectly considered non-synthesisable due to overflow

0.6.17 June 9th 2016

  • Fixes bugs:
    • Eq instance of Vec sometimes not synthesisable

0.6.16 June 7th 2016

  • New features:
    • DEC transformation also lifts HO-primitives applied to “interesting” primitives (i.e. zipWith (*))
  • Fixes bugs:
    • replicate unfolded incorrectly #150
    • imap is not unrolled #151

0.6.15 April 7th 2016

  • New features:
    • Up to 2x reduced compilation times when working with large Vec literals
  • Fixes bugs:
    • Bug in DEC transformation throws CLaSH into an endless loop #140

0.6.14 March 21st 2016

  • New features:
    • Also generate testbench for circuits without input ports #135
  • Fixes bugs:
    • clockWizard broken #49

0.6.13 March 14th 2016

  • Fixes bugs:
    • Not all lambda’s in a function position removed

0.6.12 March 14th 2016

  • Fixes bugs:
    • Not all lambda’s in a function position removed due to bad eta-expansion #132

0.6.11 March 11th 2016

  • New features:
    • Add support for HDL synthesis tool specific HDL generation
    • Preserve more Haskell names in generated HDL #128

0.6.10 February 10th 2016

  • New features:
    • hdl files can be written to a directory other than the current working directory #125
  • Fixes bugs:
    • caseCon transformation does not work on non-exhaustive case-expressions #123
    • Primitive reductions don’t look through Signal #126

0.6.9

  • Fixes bugs:
    • case undefined of ... should reduce to undefined #116
    • Type families obscure eligibility for synthesis #114

0.6.8 January 13th 2015

  • New features:
    • Support for Haskell’s: Char, Int8, Int16, Int32, Int64, Word, Word8, Word16, Word32, Word64.
    • Int/Word/Integer bitwidth for generated HDL is configurable using the -clash-intwidth=N flag, where N can be either 32 or 64.
  • Fixes bugs:
    • Cannot reduce case error ... of ... to error ... #109

0.6.7 December 21st 2015

  • Support for unbound-generics-0.3
  • New features:
    • Only look for ‘topEntity’ in the root module. #22

0.6.6 December 11th 2015

  • New features:
    • Remove all existing HDL files before generating new ones. This can be disabled by the -clash-noclean flag. #96
    • Support for clash-prelude 0.10.4

0.6.5 November 17th 2015

  • Fixes bugs:
    • Integer literals used as arguments not always properly annotated with their type.

0.6.4 November 12th 2015

  • Fixes bugs:
    • Reversing alternatives is not meaning preserving for literal patterns #91
    • DEC: root of the case-tree must contain at least 2 alternatives #92

0.6.3 October 24th 2015

  • New features:
    • Improve DEC transformation: consider alternatives before the subject when checking for disjoint expressions.
  • Fixes bugs:
    • DEC: don’t generate single-branch case-expressions #90

0.6.2 October 21st 2015

  • Fixes bugs:
    • DEC: Subject and alternatives are not disjoint #88

0.6.1 October 16th 2015

  • New features:

    • Support for clash-prelude 0.10.1

    • Transformation that lifts applications of the same function out of alternatives of case-statements. e.g.

      case x of
        A -> f 3 y
        B -> f x x
        C -> h x
      

      is transformed into:

      let f_arg0 = case x of {A -> 3; B -> x}
          f_arg1 = case x of {A -> y; B -> x}
          f_out  = f f_arg0 f_arg1
      in  case x of
            A -> f_out
            B -> f_out
            C -> h x
      
  • Fixes bugs:

    • Case-statements acting like normal decoder circuits are erroneously synthesised to priority decoder circuits.

0.6 October 3rd 2015

  • New features:
    • Support for clash-prelude 0.10
    • Add ~INDEXTYPE tag: primitives get access to the Index clash-prelude type
    • Add ~IF construct: primitives can do conditional templating
    • Unroll “definitions” of the following primitives: fold, dfold, foldr

0.5.13 September 21st 2015

  • Fixes bugs:
    • Performance bug: top-level definitions of type “Signal” erroneously inlined.

0.5.12 September 14th 2015

  • New features:

    • Completely unroll “definitions” of some higher-order primitives with non-representable argument or result vectors: It is now possible to translate e.g. f xs ys = zipWith ($) (map (+) xs) ys :: Vec 4 Int -> Vec 4 Int -> Vec 4 Int
  • Fixes bugs:

    • topLet transformation erroneously not performed in a top-down traversal
    • Specialisation limit unchecked on types and constants
    • Vector of functions cannot be translated #25
    • CLaSH fails to generate VHDL when map is applied #78

0.5.11 September 7th 2015

  • Fixes bugs:
    • Clash running out of memory on Simple-ish project #70
    • CLaSH.Sized.Vector.:> was not allowed as a function argument to HO-primitives

0.5.10 August 2nd 2015

  • Fixes bugs:
    • Make testbench generation deterministic
    • Compile against unbound-generics-0.2

0.5.9 July 9th 2015

  • Fixes bugs:
    • coreView didn’t look through newtypes of the form: newtype Foo a = MkFoo (Maybe a)

0.5.8 June 26th 2015

  • Fixes bugs:
    • Allow text and tags in ~SIGD black box construct

0.5.7 June 25th 2015

  • New features:

    • Support for copying string literals from Haskell to generated code
    • Collect and copy data-files
  • Fixes bugs:

    • Signals declared twice when not using a clock-generating component #60
    • This piece of code eat up all CPU when generating verilog #62

0.5.6 June 3rd 2015

  • New features:
    • Support Verilog backend
    • Generated component names are prefixed by the name of the module containing the topEntity

0.5.5 May 18th 2015

  • New features:

    • Make inlining and specialisation limit configurable
    • Make debug message level configurable
  • Fixes bugs:

    • Netlist: ensure that the arguments of a component instantiation are always simple variables
    • CaseCon transformation: ensure that we run the compile-time evaluator on the subject before handling the one-alternative case
    • Emit a warning if a function remains recursive, instead of producing an error: compilation can still be successful if the function is an argument to a higher-order blackbox that doesn’t use the function.
    • Emit a warning if inlining limit is reached, instead of producing an error: compilation can still be successful if the function is an argument to a higher-order blackbox that doesn’t use the function.
    • Always inline terms that have a type of kind Constraint

0.5.4 May 10th 2015

  • New features:
    • Add ~COMPNAME tag: primitives get access to the component name in which they are instantiated

0.5.3 May 5th 2015

  • New features:
    • TopEntity wrappers are now specified as ANN annotation pragmas
  • Fixes bugs:
    • Lost system1000 clock in VHDL generation… #53
    • flattenCallTree sometimes introduces free variables

0.5.2 May 1st 2015

  • New features:
    • Generate wrappers around topEntity that have constant names and types

0.5.1 April 20th 2015

  • GHC 7.10 support

0.5 March 11th 2015

  • New features:

    • Simplify BlackBox handling, and improve VHDL generation. #47
    • Use unbound-generics. #48
  • Fixes bugs:

    • VHDL generation error: wrapper for sum-of-products type. #44

0.4.1 February 4th 2015

  • Fixes bugs:
    • Treat BlackBox expressions as declarations when DC args. #37
    • Don’t inline recursive closed bindings

0.4 November 17th 2014

  • New features:

    • Support for clash-prelude 0.6
  • Fixes bugs:

    • Ambiguous type: ‘std_logic_vector’ or ‘std_ulogic_vector’ #33

0.3.2 June 5th 2014

  • Fixes bugs:
    • VHDL array constant ambiguous #18
    • Exception: can’t create selector #24
    • Calls to vhdlTypeMark don’t result to inclusion of VHDL type in types.vhdl #28

0.3.1 May 15th 2014

  • New features:

    • Make ANF lift non-representable values #7
    • Hardcode fromInteger for Signed and Unsigned #9
    • Replace VHDL default hole by error hole #13
  • Fixes bugs:

    • Type families are not expanded #3
    • Exception: CLaSH.Netlist.VHDL(512): fromSLV: Vector 13 Bool #5
    • Incorrect vhdl generation for default value in blackbox #6
    • Duplicate type names when multiple ADTs need the same amount of bits #8
    • Circuit testbench generation with MAC example fails#15
  • Code improvements:

    • Refactor Netlist/BlackBox #10
    • CPP special-case conversion of Control.Exception.Base.irrefutPatError #11