non-atomic Copper waits for MrgCop?

[Samurai_Crow]

Hello,

I've been carefully considering what shape Copper handling support should take on AROS 68k and comparing it to the way that it works on AmigaOS 3.1. One of the biggest problems with MrgCop in Graphics.library on 3.1 is that it treats the CWAIT macro as an atomic delay and won't let the programmer insert additional CMOVEs from another partial Copper-list in while the first one is waiting.

In order to try to write a CYIELD macro, I need to know how to implement NXTLIST in a macro. Specifically, I need to be able to insert a NXTLIST at the end of the current CopList structure, allocate a new CopList structure using the DyOffset of the y coordinate passed to the CYIELD macro, and finally, start the next CopList with a CWAIT or so (depending on the x and y coordinates used) that will allow other CopList structures to be sorted by the DyOffset so that they will be interleaved.

If somebody could write an example code in C (hopefully not too trivial) that uses NXTLIST (or the u3.nxtlist union member) to be used, it might help me see what needs to be done.