Re: CVS commit: src/sys/arch/m68k/m68k

[Nat Sloss <nathanialsloss%yahoo.com.au@localhost>]

On Fri, 4 Apr 2025 22:37:50 Tetsuya Isaki wrote:
> At Thu, 3 Apr 2025 14:00:16 +0200,
> 
> Martin Husemann wrote:
> > > So these all nops are never executed just before any of f-line
> > > instructions.
> > 
> > Can you also please explain how you got at that NOP-after-f-line
> > woraround? The Motorola errata text (at least the versions I found on
> > the wayback machine) does not actually recommend this (it mentions NOP
> > only for the instructions close to end of page bug).
> 
> The nop-before-f-line (correction: s/after/before/) workaround is
> noted as E4 at the original PR port-mac68k/13078.
> But I can't find any other materials...
> 
> And I know about the exception-at-end-of-page bug (No.10), too.
> Whether this happens depends on the address of an unimplemented
> floating point instruction.  The nop-before-f-line workaround
> affects (It may become to avoid or may become to hit) but doesn't
> improve the errata No.10.
> ---
> Tetsuya Isaki <isaki%pastel-flower.jp@localhost / isaki%NetBSD.org@localhost>


The changes to the context switch in sys/m68k have been reverted and the nop 
insertion by gas(1) has been turned off by default.

Best regards,

Nat