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Re: [MiNT] XaAES sources for FreeMiNT 1.16.3

Johan Klockars wrote:

IMO, it should never be possible for a user program/library to write
directly to video memory.


If it is technically possible, like on ST, why not allowing this ? If
this is hidden under a clean API, there is nothing wrong.


Drivers for graphics accelerators will need to access hardware
registers


Some hardware registers are accessible in user mode. We have discovered
this recently with EtherNAT.


and, unless I'm mistaken, the NatFeat instructions necessary
for accelerated graphics under ARAnyM do not work in user mode.


ARAnyM can be modified to be more efficient.

However I agree, most drivers have to access supervisor mode to do their
work.


You also need to consider that the VDI would sometimes be really
unhappy if called from multiple contexts at once. So, you'd need
kernel based locking for at least some things.


Sure, the VDI has to use some mutex or similar. So the VDI has to call
the kernel, as every user program.

--
Vincent Rivière