Re: Signficant bugfix to my emulator

On Mon, 2024-01-01 17:55:50 -0500, Mouse <[email protected]> wrote:
> > Just ftr:  My invocation is like this:
> 
> [...]
> >                 -deqna 0disable
> 
> Aha.  If I try it with no DEQNA, I find that the NetBSD ISO panics for
> me too (I guess with XQA0 present, it doesn't get far enough to).
> 
> I did the full-tracing thing again: set output breaks on "mscpbus1:"
> and "panic:", then, when the first one tripped, turn on full tracing
> and slow down clock ticks by a factor of 100.  Turns out it's doing an
> LDPCTX when not on the interrupt stack.  This is either a bug in the
> kernel or fallout from something else wrong with the emulator.  Given
> the recent successes on real hardware, I'm more inclined to suspect the
> latter.
> 
> In the trace from the crash, the offending instruction is
> 
> (217086589 001f0000) 8000079a: 06                        ldpctx  
> 
> I've put the trace, from "mscpbus1:" to "panic:", up on
> ftp.rodents-montreal.org, in
> /mouse/misc/vax/2024-01-01.15:26:33.nb-iso-no-deqna, in case anyone
> wants to have a look.  (It's a much bigger file than the other files I
> put up for fetch - this one is 26163980 bytes.)  There are two ldpctx
> instructions executed in the trace; the second one is the problematic
> one.  I recommend searching for "ldpctx".

Looking at the pre-executed instructions, this must be
softint_process (in /usr/src/sys/arch/vax/vax/subr.S), so generally
this ist softint-handling code.

MfG, JBG (who's now going to bed)

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