2D R2C/C2R transform on NEON gives bus error

anthonix / ffts

The Fastest Fourier Transform in the South

http://anthonix.com/ffts

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2D R2C/C2R transform on NEON gives bus error #30

Open zougloub opened 10 years ago

zougloub commented 10 years ago

Hi,

I'm using ffts to process pictures, and was about to switch from naive C2C transforms to R2C/C2R, when I noticed that it was crashing on ARM, because of alignment issues. The nd transform is calling the 1d transform on buffers like: a=0xb6dd3400 b=0xb6e59408.

I'm checking whether I can fix that...

zougloub commented 10 years ago

Issue is worked around by disabling inline assembly in ffts_real.c, in the functions ffts_execute_1d_real() and ffts_execute_1d_real_inv(). Performance is still acceptable.

zougloub commented 9 years ago

Hi Anthony, please consider cherry-picking commit https://github.com/zougloub/ffts/commit/73d060ebc151c1136f39b029b98e55d86ed4047d that addresses this issue (by performing an unaligned access).