RPI3 Hackathon at BSDCan/Dev SUmmit

[Russell Haley]

So just in looking for answers I see that the ARM developers cross
build page is out of date.

https://wiki.freebsd.org/FreeBSD/arm/crossbuild

and to be nit picky, the aarch64 pages sit outside the ARM section in
the main wiki area. Shouldn't AARCH64 be a subset of ARM? Even if they
are not re-organized, perhaps a short description about what each
platform moniker means?

Cheers,

Russ

On Wed, Jun 8, 2016 at 12:30 PM, Isaac (.ike) Levy
<ike at blackskyresearch.net> wrote:
> Thanks Russ, All,
>
>> On Jun 8, 2016, at 3:22 PM, Russell Haley <russ.haley at gmail.com> wrote:
>>
>> On Wed, Jun 8, 2016 at 11:56 AM, Isaac (.ike) Levy
>> <ike at blackskyresearch.net> wrote:
>>>
>>>> On Jun 8, 2016, at 2:28 PM, Shawn Webb <shawn.webb at hardenedbsd.org> wrote:
>>>>
>>>> Your builds would be ARMv7, correct? As far as I know, there are no
>>>> ARMv8 BeagleBone boards.
>>>
>>> Oh, I could be very mistaken- perhaps someone on list could help me understand this- (searching the web isn't helping me here),
>>>
>>> Can anyone on list here help me clarify the ARMv7 or ARMv8 architectures?
>>
>> Oh, oh, now you've done it...  ha ha. This is very very very confusing
>> due to both marketing terms and some incongruency in terminology. I'm
>> just an amateur but I'm gonna take a shot at this so anyone who knows
>> better please feel free to correct me.
>>
>> - Cortex-A8 is a marketing term for a specific processor design. This
>> is an "ARM Ltd." design that can be licensed by anyone.
>>
>> - ARMv6, ARMv7 and ARMv8 are all different ARM *instruction sets*.
>> Different processors and families use different instruction sets (also
>> license-able by anyone to design their OWN processors).
>>
>> - The Beaglebone series uses the Texas Instruments am33XX processor
>> family, which I think includes designs of both ARMv6 and ARMv7
>> variants. The ARMv7 variants are based on the Cortex-A8 design. The
>> RPI2 uses a Broadcomm chip that is also a Cortex-A8 based processor
>> (ARMv7).
>>
>> - Within FreeBSD, ARMv6 and ARMv7 are represented by one architecture
>> (ARCH) which is called ARMv6 (as was recently lamented by Mr. Lapore).
>> That's why you can't find reference to ARMv7.
>>
>> (This is where i start getting fuzzy on details)
>>
>> -The RPI3 is a 64 bit variant of the PRI development board.  ARMv8 is
>> the Arm 64 bit family of instruction sets. In FreeBSD, it's called
>> AARCH64. That's why you won't see it mentioned as ARMv8.
>>
>> Hence, when referring to RPI 1, 1+ 2 or 2B, the term armv6 is thrown
>> around and when discussing the RPI3 the term AARCH64 is used.
>>
>> I think...? tee hee.
>>
>> Cheers,
>>
>> Russ
>
> "RISC architecture is gonna change everything."
>
> I really appreciate this shot at an explanation, and would hazzard to say that clarity here is perhaps the biggest problem ARM platforms have going for them :)  For users, far more confusing than Itanium vs. AMD64 ever was!
>
> Thanks again Russ.
>
> Best,
> .ike
>
>
>