Re: Moving VAX into 21 century :-)

[Paul Koning <paulkoning%comcast.net@localhost>]

> On Oct 1, 2019, at 5:21 PM, Kamil Rytarowski <n54%gmx.com@localhost> wrote:
> 
> On 29.09.2019 22:38, Maciej W. Rozycki wrote:
>> On Thu, 5 Sep 2019, Chris Hanson wrote:
>> 
>>> I’d naïvely expect NetBSD to use the standard calling conventions for an 
>>> architecture (if such a thing exists) as part of interoperating with 
>>> other code written for that architecture.
>> 
>> Oh, it happens all the time that new ABIs are defined for a given CPU 
>> architecture as circumstances change or lessons are learnt from past 
>> mistakes, and they can all coexist in a single running system if required, 
>> as the so called multilibs.  Otherwise we'd be stuck with wrong solutions 
>> forever.
>> 
>>  Maciej
>> 
> 
> Moving out CALLS is a drastic decision. I considered CALLS personally as
> a feature of VAX as we don't need to care too much about ABIs, CALLS
> pretty much normalizes it among all users. The shortcoming of this is of
> course some performance impact.. but I would be interested to see real
> numbers (like kernel booting time) of redoing the work done by CALLS vs JSB.

I wonder if it would be possible to hand-code some tests comparing CALLS with the equivalent JSB based call.  It wouldn't surprise me if the difference were smaller than you might expect.  After all, CALLS (and CALLG probably to a lesser extent) are everywhere, so VAX designers had significant incentive to work on making those instructions go fast.

	paul