It seems that you're right - ISO C doesn't have standard macros for this. That said, since this code is ARM-specific, and you are already leveraging the ACLE h

It seems that you're right - ISO C doesn't have standard macros for this. That said, since this code is ARM-specific, and you are already leveraging the ACLE header <arm_neon.h>, I think that a negative test for __ARM_BIG_ENDIAN is appropriate. https://developer.arm.com/documentation/101028/0012/5--Feature-test-macros https://developer.arm.com/documentation/101028/0012/5--Featu...