Documentation.SBV.Examples.CodeGeneration.Uninterpreted

Demonstrates the use of uninterpreted functions for the purposes of code generation. This facility is important when we want to take advantage of native libraries in the target platform, or when we'd like to hand-generate code for certain functions for various purposes, such as efficiency, or reliability.

Documentation

>>> -- For doctest purposes only:
>>> import Data.SBV

shiftLeft :: SWord32 -> SWord32 -> SWord32

A definition of shiftLeft that can deal with variable length shifts. (Note that the `shiftL` method from the Bits class requires an Int shift amount.) Unfortunately, this'll generate rather clumsy C code due to the use of tables etc., so we uninterpret it for code generation purposes using the cgUninterpret function.

tstShiftLeft :: SWord32 -> SWord32 -> SWord32 -> SWord32

Test function that uses shiftLeft defined above. When used as a normal Haskell function or in verification the definition is fully used, i.e., no uninterpretation happens. To wit, we have:

>>> tstShiftLeft 3 4 5
224 :: SWord32

>>> prove $ \x y -> tstShiftLeft x y 0 .== x + y
Q.E.D.

genCCode :: IO ()

Generate C code for "tstShiftLeft". In this case, SBV will *use* the user given definition verbatim, instead of generating code for it. (Also see the functions cgAddDecl, cgAddLDFlags, and cgAddPrototype.)