Re: Technical support

[Thomas Huth]

On 24/03/2024 19.45, Luca Vajen wrote:
> Hello,
> I'm not sure if this is the right place to ask for help. I guess in the 
> worst case you might get a laugh out of this. There's an old game I would 
> like to play again and someone made a ready-to-play version using QEMU. See 
> the corresponding link 
> on https://werbespiel.blogspot.com/2010/07/tony-friends-new-adventures.html 
> . That itself is handy, but the game runs too fast on my PC and I don't know 
> how to slow it down. I didn't find an answer anywhere how to limit the 
> speed. Does someone have an idea?

QEMU is a JIT emulator that normally tries always to go as fast as possible, 
so for emulating old software that is sensitive to timing, you might need 
another emulator instead.
However, there are also some few tricks that can be used to slow down QEMU:

1) Build QEMU with --enable-debug ... that turns off optimizations during
   compilation and thus emulation gets slower

2) Try running with "-accel tcg,one-insn-per-tb=on" (or "-singlestep" when
   you are using older QEMU binaries), that will disable the advantage of
   JIT and emulate each instruction separately, slowing down the emulation
   quite a bit, too.

 HTH,
  Thomas