29 Sep 2020 16:24
|Probably the copperlist at some point resets the bitplanes pointers and this instructions are never executed in regular/old amigas because usually the speed of the copper is fixed and when the beam reaches the end the copperlist is reexecuted from scratch.|
It 's only my assumption, and it is probably wrong.
If Gunnar changes this behaviour (increasing the copper speed) I fear a lot of legacy code would break, for example copperchunky usually relies on the fact that the copper takes the equivalent of some pixels to perform a move, if the v4 is faster that could lead to some incorrect behaviours and old copperchunky routines cant work as expected.
As Gunnar stated in our meeting, Amiga is a quite complicated system and my opinion is that sometimes making all the coprocessors work correctly in sync with the cpu is hard.
To complicate even more things, old programmers used tricks and banged the hardware so hard that compatibility can be an issue even between old commodore Amigas.