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Problem with NEON for I.MX 6

Question asked by 曦 刘 on Nov 11, 2014
Latest reply on Nov 20, 2014 by 曦 刘

Hello, please excuse me for taking some of your time.


We have a program using I.MX 6 with android ndk platform. We are currently optimize our C++ code with NEON, and encountered with some problems:


  when we turn on the neon flag i.e. "-mfpu=neon", a bus error occrued while the code runs well with no error with flag "mfpu=vfpv3d16".


With further investigate, we found that gcc assume neon is by default with vfpv3d32, so we guess the error may be caused by vfp instruction which using d16-d31 (because gcc assumes that d16-d31 is available when the neon flag is used).


However, the I.MX 6 is configured with neon + vfpv3d16 which means that there are only 16 d reg for vfp. We want to know if there is any possibility that I.MX 6 can have NEON worked (if the answer is yes, then how?), or this problem can not be solved for this chip?


We would be greatly appreciated if you could answer our question. Thank you very much for your consideration.


Best regards