The problem with this game is that they have a very high
timer frequency so irq0 will be active almost always (at
least when runIRQs is called), and irq1 (keyboard) doesn't
get served. Game works fine otherwise.

Maybe runIRQs should be called after an IRET.

wd

So, after reading your technical post, i am surmising we need a patch for it. 😒 Have anybody checked for available patches or even contacting the developers.

Well generally it gets technically if i do NOT have
any working patch 😀

Removing the #if 0 in write_data (pic.cpp)
seems to render the keyboard to work correctly.
Qbix/harekiet recommended this one too, but
i don't know if it has any side-effects.

wd

What exactly is that code doing? How does it change the behavior of the emulated PIC? It's so hard to understand the DOSBox code due to lack of comments/documentation 🙁

Here's the code I'm talking about:

1#if 0
2		if (PIC_IRQCheck) {
3			CPU_CycleLeft+=CPU_Cycles;
4			CPU_Cycles=0;
5		}
6#endif

PIC_IRQCHECK is a variable that contains the lists of irqs that should be handled. (say their irq line is up)

so if there are irqs that have their irq line up : add the current (yet to do) amount of cpu instructions to the big value
and set the counter to zero.

this results in stopping the dosbox cpu emulation and letting it check it's irq's.

That code is and off now and then. It's a relative expensive operation.(that stopping the machine/checking ints/restarting machine)