A lot of really good changes came to VOLK with v1.4. It wouldn't have been possible without the following contributors:



Generally, there are a lot of kernel changes and some minor dependency changes. I'm trying to remove boost as a dependency and we've introduced mako templates rather than the old Cheetah-templates to keep in line with GNU Radio. There are also several new CI files that support appveyor, travis-ci, and gitlab. Right now all pull requests must pass travis-ci.


The easiest way to show these changes is simply with two lists:

New kernels

  • 32 bit reversal
  • 32f_s32f_s32f_mod_range_32f
  • double precision (64f_XXX...)
    • multiply
    • add
  • 32f_64f_multiply_64f
  • add 32f_64f_add_64f
  • 32fc_x2_add_32fc

New proto-kernels by architecture


Note that in some cases an unaligned version was added where an aligned version already existed

  • volk_64f_convert_32f
  • volk_64f_x2_max_64f
  • volk_64f_x2_min_64f
  • volk_32f_x2_add_32f
  • 32i_x2_and_32i
  • 32i_x2_or_32i
  • conjugate dot products
  • 32f_accumulator_32f
  • stddev_and_mean
  • volk_32f_* kernels
  • 32f_x2_divide_32f
  • 32f_x2_dot_prod_16i
  • volk_32f_s32f_normalize
  • volk_32f_s32f_stddev_32f
  • volk_32f_sqrt_32f
  • volk_32f_x2_max_32f
  • volk_32f_x2_min_32f
  • 32f_x2_s32f_interleave_16ic
  • 32f_x2_subtract_32f
  • 32f_x2_s32f_interleave_16ic
  • 32f_x2_subtract_32f
  • 32f_x2_subtract_32f
  • 32f_x2_s32f_interleave_16ic
  • volk_8ic_s32f_deinterleave_*
  • 32f_log2_32f
  • volk_32f_s32f_convert_8i and 16i


  • move all neonasm to aligned protokernels
  • added ARM version of volk_32u_reverse_32u (RBIT)
  • volk_32fc_x2_divide_32fc
  • volk_32fc_32f_add_32fc
  • volk_32f_x2_divide_32f
  • volk_8i_s32f_convert_32f

Additionally, there are new protokernel intrinsics available for use in writing new kernels.

Then, we also had some general kernel and protokernel bug fixes and using proper type-named C functions which happened to increase performance:

The polarbutterfly went through some heavy refactoring and bug fixes as well as adding an AVX version. Fix GH issue #139 for 32fc_index_max_* kernels resulting in a slightly wrong index being returned. Fix bug 106 (volk_64u_popcnt bug in generic implementation)

CI and Builds

As previously mentioned there are appveyor, travis-ci, and gitlab CI files available. There is a travis-ci instance checking all pull requests at https://travis-ci.org/gnuradio/volk/ and a gitlab mirror running CI checks at https://gitlab.com/n-west/volk.

While working on these CI files the kernel tests were split in to individual ctest targets so that each kernel is its own test rather than running them as a monolithic binary. This allows parallel testing, but mostly enables easier diagnostics when a test fails. The readme is now a markdown file that renders well on GitHub and Gitlab along with the travis-ci status as a badge.

Within this release two tools were run that reorganized includes and fixed a bunch of typos within code.

As part of the attempt to build VOLK without boost a bunch of app and build utilities were written to replace boost-code. This shouldnt be visible to the user, but will hopefully make future builds easier and smaller with fewer build and run-time dependencies. Builds with python 2.7 and 3 should work-- although six is required for python2.7 support.

Some build changes make it easier to do a relocatable build and order all files before building so that building from a particular revision (from now on) should be reproducible across machines building the same architectures. To use a relocatable install use the VOLK_PREFIX environment variable. This should support snaps (Canonical packaging environment).


modtool: update the cmake find module for volk mods
modtool: deconflict module include guards from main volk