Messages in this thread | | | Date | Tue, 29 Jan 2013 14:13:29 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [RFC] arm: use built-in byte swap function |
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On Mon, Jan 28, 2013 at 07:30:33PM -0600, Kim Phillips wrote: > AFAICT, arm gcc got __builtin_bswap{32,64} support in 4.6, > and for the 16-bit version in 4.8.
Hmm.
$ /usr/local/aeabi/bin/arm-linux-gcc --version arm-linux-gcc (GCC) 4.5.4 Copyright (C) 2010 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ for a in armv3 armv4 armv4t armv5t armv5te armv6k armv6 armv7-a; do \ echo $a:; \ for f in 16 32 64; do \ echo 'unsigned foo(unsigned val) { return __builtin_bswap'$f'(val); }' | \ /usr/local/aeabi/bin/arm-linux-gcc -x c -S -o - - -march=$a | grep 'bl'; \ done; \ done
produces:
armv3: bl __builtin_bswap16 armv4: bl __builtin_bswap16 armv4t: bl __builtin_bswap16 armv5t: bl __builtin_bswap16 armv5te: bl __builtin_bswap16 armv6k: bl __builtin_bswap16 armv6: bl __builtin_bswap16 armv7-a: bl __builtin_bswap16
So, this compiler (4.5.4) has support for 32-bit and 64-bit bswaps across all our architectures, but not the 16-bit ones.
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