On Tue, 20 Jun 2000, Albert Beevendorp wrote:
> >Maybe a greater advance in the new MSX graphics scheme would be RAM-mapped
> >VRAM (it is VRAM being directly accesible by the CPU). In this way, all
> >VRAM access by the CPU would be MUCH faster: just put the value you want
> >where you want, instead of OUTing the address and then the value. Also,
> >the new VDP should have its own address space mapped to this VRAM, so both
> >the CPU and the VDP can access this memory, thus keeping
> >backwards compatibility with older generations, and making the new MSX
> >video structure much faster.
>
> I don't think that is such a good idea, because of accidentally overwriting
> vdieo-data with other data and you could get an access conflict between CPU
> and VDP when they try to access both at the same time. It's pretty hard to
> get that working properly and even still... timing, as for a game timing is
> everything.
We currently have this problem, because we're using a CPU without memory
protection. Any memory area can be (accidentally or not) overwritten. This
problem is already there, and adding RAM-mapped VRAM wouldn't add any new
trouble.
Regards,
"Social engineering is a very common practice in the underground, and almost
magically effective. Human beings are almost always the weakest link in
computer security."
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