Re: Preparation for creating netbsd-7 branch

[Matt Thomas <matt%3am-software.com@localhost>]

On Jul 21, 2014, at 11:23 AM, Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> 
wrote:

> matt@ wrote:
> 
>> On Jul 21, 2014, at 10:56 AM, Izumi Tsutsui 
>> <tsutsui%ceres.dti.ne.jp@localhost> wrote:
>> 
>>> rjs@ wrote:
>>> 
>>>> Izumi Tsutsui wrote:
>>>>> skrll@ wrote:
>>>>>> I'd guess
>>>>>> 
>>>>>> MACHINE=hpcarm        MACHINE_ARCH=earmv4
>>>>>> 
>>>>>> Maybe the port-masters/users can test?
>>>> 
>>>> I can test hpcarm on an iPAQ.
>>> 
>>> Ok, good to hear.
>>> 
>>>>> Unfortunately all these ports are orphaned.
>>>> 
>>>> There were updates to hpcarm recently to get it to work on WZERO3
>>>> hardware, what is needed for it not to be considered orphaned ?
>>> 
>>> "orphaned" means there is no portmainter to make a decision.
>>> http://www.netbsd.org/people/port-maintainers.html
>>> 
>>> I have W-ZERO3 and Zaurus machines, but I'm not so motivated
>>> because I'm not sure what's the actual benefits and risk/concerns
>>> on switching to earm on such XScale generation machines.
>>> (most important part is lack of migration method, of course)
>> 
>> the default processor for earm was chosen so that xscale and above
>> would get smaller code and slightly higher performance.
>> 
>>> Is there any documents/articles that describe earm on NetBSD?
>>> If not, we won't have enough brave users.
>> 
>> The fact that NetBSD is finally using the ABI that ARM recommends
>> and linux has been using for years?  The apcs (oabi) is not supported
>> anymore.
> 
> What about acorn26 and acorn32?

Are you willing to step up and fix any apcs32 bugs in gcc?

I have no idea if acorn26 still runs (I've made a significant
effort to ensure it does).  It would greatly simplify
the ARM world if it would just die. :)

acorn32 uses an armv3 processor which I have no idea if EABI 
supports.  earmv3 anyone?  Anyone willing to give it a shot?

How many machines running out there run NetBSD?  If there are more
acorn26 machines than I can count with my thumbs, I'd be surprised.
acorn32?  Single digits?  

Sometimes you just have to say goodbye (pc532) to a supported platform.

> What about SA-1100 iPAQ and Jornada in hpcarm?

earmv4 will support them.  

Let me be clear about something, for softfloat, the sole difference 
between APCS-32 and AAPCS is that the alignment for doubles and 
long longs changed from 4 to 8 bytes and consequently the stack must 
be kept 8 byte aligned.  Excluding hardfloat support, that it the 
only ABI difference between the two.

Thus compiling for any earm variant is, for the most part, a simple 
recompile for the new ABI.

> Linux no longer supports these ancient machines, I guess.
> 
> Anyway, lack of documentation is still the serious problem.

I am exactly the wrong person to write it.  I know the space 
intimately so I don't know what a new person needs to know
because it would never occur to me.