On 15/10/2021 09:40, Laurent Vivier wrote:
Le 13/10/2021 à 23:21, Mark Cave-Ayland a écrit :
This allows the programmer's switch to be triggered via the monitor for
debugging
purposes. Since the CPU level 7 interrupt is level-triggered, use a timer to
hold
the NMI active for 100ms before releasing it again.
I'm wondering if Qemu provides another way to have a level-triggered interrupt
in this case.
I' tried to see if keeping the button pressed on a mac kept the IRQ up (as QMP
NMI does), but a real
mac is too slow and has to many things to display it was not really
conclusive...
When writing the patch I rebased the outstanding MacOS patches onto the branch,
installed Macsbug into MacOS and used "info nmi" to break into it.
Testing glue_nmi() with:
GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 1);
GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 0);
i.e. a simple pulse didn't launch MacsBug at all. Keeping the NMI high launches
MacsBug (which is usable) but then as soon as you exit MacsBug with ES, MacsBug
breaks immediately again making it impossible to return to the Finder. Adding the
timer allows launching MacsBug and then exiting/re-entering MacsBug again on demand
as expected.
ATB,
Mark.
