RPI3 Hackathon at BSDCan/Dev SUmmit

[Isaac (.ike) Levy]

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