diff options
author | Mathias Agopian <mathias@google.com> | 2012-11-04 02:03:49 -0800 |
---|---|---|
committer | Mathias Agopian <mathias@google.com> | 2012-11-05 01:03:43 -0800 |
commit | e8299af5665bf9c396466c33b9b16a84fe78c7f6 (patch) | |
tree | f3356a4917a4ec9827d70bc9acf80feac7c1360c /tools/resampler_tools | |
parent | 50ebdf2086b645b9b703a6d489238767a9afb34f (diff) | |
download | frameworks_av-e8299af5665bf9c396466c33b9b16a84fe78c7f6.zip frameworks_av-e8299af5665bf9c396466c33b9b16a84fe78c7f6.tar.gz frameworks_av-e8299af5665bf9c396466c33b9b16a84fe78c7f6.tar.bz2 |
change how we store the FIR coefficients
The coefficient table is now transposed and shows
much better its polyphase nature: we now have a FIR
per line, each line corresponding to a phase.
This doesn't change at all the results produced by
the filter, but allows us to make slightly better
use of the data cache and improves performance a bit
(although not as much as I thought it would).
The main benefit is that it is the first step
before we can make much larger optimizations
(like using NEON).
Change-Id: Iebf7695825dcbd41f25861efcaefbaa3365ecb43
Diffstat (limited to 'tools/resampler_tools')
-rw-r--r-- | tools/resampler_tools/fir.cpp | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/tools/resampler_tools/fir.cpp b/tools/resampler_tools/fir.cpp index ea3ef50..cc3d509 100644 --- a/tools/resampler_tools/fir.cpp +++ b/tools/resampler_tools/fir.cpp @@ -195,7 +195,8 @@ int main(int argc, char** argv) // total number of coefficients (one side) - const int N = (1 << nz) * nzc; + const int M = (1 << nz); + const int N = M * nzc; // generate the right half of the filter if (!debug) { @@ -220,22 +221,25 @@ int main(int argc, char** argv) } if (!polyphase) { - for (int i=0 ; i<N ; i++) { - double x = (2.0 * M_PI * i * Fcr) / (1 << nz); - double y = kaiser(i+N, 2*N, beta) * sinc(x) * 2.0 * Fcr; - y *= atten; + for (int i=0 ; i<=M ; i++) { // an extra set of coefs for interpolation + for (int j=0 ; j<nzc ; j++) { + int ix = j*M + i; + double x = (2.0 * M_PI * ix * Fcr) / (1 << nz); + double y = kaiser(ix+N, 2*N, beta) * sinc(x) * 2.0 * Fcr; + y *= atten; - if (!debug) { - if ((i % (1<<nz)) == 0) - printf("\n "); - } + if (!debug) { + if (j == 0) + printf("\n "); + } - if (!format) { - int64_t yi = floor(y * ((1ULL<<(nc-1))) + 0.5); - if (yi >= (1LL<<(nc-1))) yi = (1LL<<(nc-1))-1; - printf("0x%08x, ", int32_t(yi)); - } else { - printf("%.9g%s ", y, debug ? "," : "f,"); + if (!format) { + int64_t yi = floor(y * ((1ULL<<(nc-1))) + 0.5); + if (yi >= (1LL<<(nc-1))) yi = (1LL<<(nc-1))-1; + printf("0x%08x, ", int32_t(yi)); + } else { + printf("%.9g%s ", y, debug ? "," : "f,"); + } } } } else { @@ -266,11 +270,6 @@ int main(int argc, char** argv) } if (!debug) { - if (!format) { - printf("\n 0x%08x ", 0); - } else { - printf("\n %.9g ", 0.0f); - } printf("\n};"); } printf("\n"); |