bits-extras: Efficient high-level bit operations not found in Data.Bits

[ bsd3, data, library ] [ Propose Tags ]

This package contains efficient implementations of high-level bit operations missing from Data.Bits. The implementation is based on GCC builtins, which translate to specialized instructions where available.

All operations in this package can also be (less efficiently) implemented in terms of Data.Bits operations.

Issues: A GCC-provided library, libgcc_s, is dynamically linked to provide software fallbacks on architectures without instructions corresponding to specific operations. This is currently only expected to work on Linux systems, and even there can lead to issues with GHCi's custom linker. A workaround for GHCi on a linux system: ln -s /lib/ /lib/

The current plan for broader support is to replace the libgcc dependency with built-in fallbacks in C or Haskell code. This needs to closely follow GCC's fall-back behaviour for each architecture. Alternative ideas would be appreciated.

Relevant Hackage tickets:


  • 0.1.3: Added a first test and tweaked documentation. No functional changes.

  • 0.1.2: Moved the Data.Bits.Atomic module to the package bits-atomic. Those operations do not depend on libgcc_s and should work wherever GCC 4.X is available. Link to bits-atomic on hackage:




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Versions [RSS] 0.1.0, 0.1.1, 0.1.2, 0.1.3
Dependencies base (>=4 && <6), HUnit, QuickCheck, test-framework, test-framework-hunit, test-framework-quickcheck2 [details]
License BSD-3-Clause
Author Gabriel Wicke <>
Maintainer Gabriel Wicke <>
Category Data
Source repo head: hg clone
Uploaded by GabrielWicke at 2010-09-20T18:26:23Z
Reverse Dependencies 4 direct, 0 indirect [details]
Executables test
Downloads 4396 total (10 in the last 30 days)
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