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Subject: Re: FCP-100: armv7 plan
To: Jan Beich <jbeich@FreeBSD.org>, Warner Losh <imp@bsdimp.com>
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Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>,
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From: John Baldwin <jhb@FreeBSD.org>
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Date: Sat, 9 Sep 2017 18:36:51 -0400
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On 9/9/17 3:25 PM, Jan Beich wrote:
> Warner Losh <imp@bsdimp.com> writes:
> 
>> On Sat, Sep 9, 2017 at 1:05 PM, Jan Beich <jbeich@vfemail.net> wrote:
>>
>>> Warner Losh <imp@bsdimp.com> writes:
>> The goal, if it doesn't work already, is for NEON to work if used,
>> but not be required, just like all the other optional features of a CPU.
> 
> FreeBSD doesn't support detecting NEON at runtime unlike Linux. Do you
> mean at compile time? If so then the following probably needs to change
> 
> $ cc -target armv7-unknown-freebsd12.0-gnueabihf -dM -E -</dev/null |& fgrep -i neon
> #define __ARM_NEON 1
> #define __ARM_NEON_FP 0x4
> #define __ARM_NEON__ 1

Re: runtime, I have patches in review to add AT_HWCAP for native FreeBSD/arm
binaries.  Right now it doesn't support a NEON hwcap but it should be easy to
add the flag using the same check to enable it that Linux does.

-- 
John Baldwin