Question

The cpu is the omap 4460, it seems to be cortex-A9, armv7, with neon, vfpu3, and the rest of the options. My main problem is, how do I make GCC “know” that the target platform has neon instructions? Since I know it’s optional on cortex-a9. I just want to make sure that the programs are compiled to at least try to use neon, as when I compile my code in GCC and tell it to use an x86 processor that has SSE, I want it to at least try to use it if it can.

I’ll update this post with the actual info from /proc/cpuinfo but until then I’ll leave it as it is, since debian’s fuse rules are biting me.

Processor   : ARMv7 Processor rev 10 (v7l)
processor   : 0
BogoMIPS    : 1194.24

processor   : 1
BogoMIPS    : 1194.24

Features    : swp half thumb fastmult vfp edsp thumbee neon vfpv3 
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x2
CPU part    : 0xc09
CPU revision    : 10

Hardware    : Tuna
Revision    : 000a
Serial      : 0149c6f40c009018

OK, with that up above. The -march= should be armv7 correct? and the -mfpu, should that be vfpv3 or should it be neon? I’m personally leaning to vfpv3, but I’m unsure at the moment…

Answer 1

With the Android NDK comes several samples, just look at the one named hello-neon and its Android.mk .

All you need to know is there, if you are only interested about the compiler options you probably only want to take into account the C flag.