xiaoxiang781216 commented on pull request #5662: URL: https://github.com/apache/incubator-nuttx/pull/5662#issuecomment-1058967929
> @xiaoxiang781216 I compiled for sabre-6quad(A9) config, and checked the compiled assemble code. In case of "-mfpu=neon-vfpv3", GCC uese NEON instructions for integer operations. In case of "-mfpu=vfpv3", GCC does not uses for integer operations. > > "-mfpu=neon-vfpv3" option may be dangerous for the kernel context switch mechanism. What do you think about this ? > It will break in the current implementation since FPU context doesn't in: https://github.com/apache/incubator-nuttx/blob/master/arch/arm/src/armv7-a/arm_vectors.S but delay to: https://github.com/apache/incubator-nuttx/blob/master/arch/arm/src/armv7-a/arm_savefpu.S If the compiler generate any code which utilize NEON instruction even without any floating point variables, the interrupted thread context will be destroyed. @anchao is preparing a patch to optimize FPU save/restore performance which can fix this problem too. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
