Ok , got it . thanks a lot for your detailed comments. Thanks, Joy
-----Original Message----- From: Yao Qi [mailto:yao...@linaro.org] Sent: Thursday, November 02, 2017 6:12 PM To: Joy Deng <joy.d...@nxp.com> Cc: linaro-toolchain@lists.linaro.org; Ting Liu <ting....@nxp.com>; Shuo Zhang <shuo.zh...@nxp.com> Subject: Re: aarch64 toolchain support NEON and vfp features On 2 November 2017 at 09:38, Joy Deng <joy.d...@nxp.com> wrote: > Hi, Qi > > Thanks a lot for your quick reply. > > As you said, in ARMv8, neon is deployed as asimd in cpuinfo, so we can > consider tool-chain will not affect the NEON function. > But, when build source code by enable neon, I can not find "-mfpu=neon" in > Makefile CFLAGS defaultly on ARMv8, while I can find it when build on ARMv7. ARMv8 is completely different from ARMv7, in many aspects. In GCC and Linux kernel, aarch64 (arm64) is different backend/port from armv7. Some options are not portable from v7 to v8. > Does it affect neon function enable? As I known, if we want enable neon, we > should build with "-mfpu=neon" flags. > In aarch64 (64-bit state in armv8), asimd is mandatory by the architecture, so aarch64 compiler can generate asimd instructions without any options. armv7 is different, because neon is optional, so you need an option to enable it. -- Yao Qi _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org https://lists.linaro.org/mailman/listinfo/linaro-toolchain
