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Does the ARM GCC support the built-in function for the "REV" command?

It is quite common for compilers to embed built-in functions for processor functions, but it's hard for me to find them. Is there a way to get the REV command (reverse word byte order) in ARM?

Where can I find a list of built-in functions?

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Is there a way to get the REV command (reverse word byte order) in ARM?

There is a more “portable” form available for all architectures. This is __builtin_bswap32 . For example, the compiler explorer ,

 unsigned int foo(unsigned int a) { return __builtin_bswap32(a); }

To give

 foo(unsigned int): rev r0, r0 bx lr

This is better than __builtin_rev , as it will be available only for specific ARM purposes (and, of course, only for ARM processors). You can use __builtin_bswap32 even on PowerPC, x86, etc.

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