We'd manually hacked _BYTE_ORDER into the arm and mips "_types.h" headers,
but not into the x86 one. Judging by upstream, _BYTE_ORDER should be in
the "endian.h" headers instead, so let's uniformly do that.
I've also ironed out some of the other differences between the different
architectures' header files too.
Bug: http://code.google.com/p/android/issues/detail?id=39824
Change-Id: I19d3af7ffd74e1c02b1b6886aec0f0d11f44ab8d
1. Make the feature test work by excluding known-deficient processors, so
we don't have to maintain a complete list of all the processors that support
REV and REV16.
2. Don't abuse 'register' to get an effect similar to GCC's +l constraint,
but which was unnecessarily restrictive.
3. Fix __swap64md so _x isn't clobbered, breaking 64-bit swaps.
4. Make <byteswap.h> (which declars bswap_16 and friends) use <endian.h>
rather than <sys/endian.h>, so we get the machine-dependent implementations.
Change-Id: I6a38fad7a9fbe394aff141489617eb3883e1e944
ARMv6 ISA has several instructions to handle data in different byte order.
For endian conversion (byte swapping) of single data words, it might be a
good idea to use the REV/REV16 instruction simply.
Change-Id: Ic4a5ed6254e082763e54aa70d428f59a0088636e
