On 10/05/2019 23:08, Computer Nerd Kev wrote:
> Dennis Lee Bieber  wrote:
>> On Thu, 9 May 2019 23:27:56 +0000 (UTC), not@telling.you.invalid (Computer
>> Nerd Kev) declaimed the following:
>>
>>> I see, as I've been looking at Pi Zero stuff, I got the impression
>>> that they were all ARM V.6, but I guess it's just that a lot of the
>>> software is built to be compatible with ARM V.6 as a common minimum
>>> spec.
>>>
>>         ARM v6 actually is /newer/ than ARM v7.
>>
>>         NO ARM core has built-in floating point -- it is an extension that
can
>> be specified when designing a chip using ARM cores. You'd have to check the
>> data sheet for the chip to determine if the designer included the floating
>> point unit. Most v7 and v6 based chips tend to have the hardware floating
>> point.
>>
>> http://single-boards.com/armv6-vs-armv7/
>> """
>>     ARMv6 architecture
>>     Includes VFPv2 optionally (usually is implemented).
>>
>>     ARMv7 architecture
>>     Includes VFPv3 optionally (usually is implemented). VFPv3 brings
>> several minor improvements. Mainly it adds a new capabilities to
>> instructions VCVT and VMOV. Some operations with floating point values can
>> run more efficiently because of the improvement.
>> """
>> (VFP => Vector Floating Point)
>>
>>
>>         v6 has Thumb-1 -- the processor has to be switched between full
>> instruction set and compressed Thumb instruction set. v7 supports Thumb-2,
>> in which full 32-bit instructions and compressed 16-bit Thumb-2
>> instructions can be intermixed without an explicit mode change.
>>
>>         v6 does not have the single-precision NEON SIMD engine. v7 may have
>> NEON, which could be useful for 2D/3D graphics processing.
>>
>>         Buried in the bottom of that link appear the key phrase... At least
for
>> Debian-provided releases it implies armhf /also uses Thumb-2/, which is not
>> available for v6 -- so needs the armel build. Though the Debian site
>> indicates that armhf also needs VFPv3.
>>
>>         BUT -- if one compiles the OS for themselves, one might be able to
>> compile without Thumb instructions, but still using VFP -- that compile
>> would be usable on both v6 and v7 chips, and hence qualify as an armhf type
>> build.
>
> And I thought this was already getting confusing just with the ARM version
> numbers. So to summarise: V.6 may have many (but not all) of the features
> of V.7 as extended features. The Debian armel builds do not use the
> floating point features of the ARM V.6 CPUs used in the PRI1/0. The armhf
> builds do, but also enable some of the ARM V.7 features not available for
> ARM V.6, so they might crash sometimes.
>
>>         So the question becomes: what does "Raspbian" (via NOOBS) contain.
>> After all, the R-Pi foundation seems to release only a single OS installer
>> file, regardless of architecture (I'm still hoping they eventually split
>> off an optional 64-bit Raspbian).  I know for a fact (just ran it) that
>> apt-get is getting armhf files for my 3B
>>
>>
>
Or you could read the Debian explanation of ARM ports as Raspbian is
built on Debian.

https://www.debian.org/ports/arm/

It explains it all.

--- SoupGate-Win32 v1.05