mechacoco at gmail.com
Sat Feb 20 18:37:56 EST 2016
On Sat, Feb 20, 2016 at 3:55 PM, Bill Pierce via Coco wrote:
> Tormod, VCC relies on (in NitrOS9) an emulation of the RTC from Cloud9 (I
> think, may be Disto) or DW4 clock in the controllers (software clock will
> be used when non is present) and OS9's "sleep" call is based on the clock.
> I'm not sure how it handles it in RSDOS, but I know the timing does not
> speed up on operations which are clock based. Maybe the clock crystal
> emulation is involved, or just based on the PC clock to replace the clock
> crystal emulation. Not really sure (it is an emulator and therefore can use
> PC resources when needed or wanted).
> It may be that it speeds up ram based instructions and not rom based
> instructions (like the 2 speedup pokes, makes more sense)... I do know that
> there are several programs that do not speed up.
> You can try it yourself, just run VCC and run Lyra (or Ultimuse3 in OS9).
> Playing a song in both slow and fast CPU modes result in the same play
> speed. Then run Musica, it plays at whatever the speed of the cpu is set.
They are likely relying on the HSYNC or VSYNC video timing. Emulators
typically maintain correct timing for those signals even when the CPU is
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