If people share the driver "illegally" as you say, then you should help them do it legally, which you didn't.

accessing PCI is not much different from other platforms which is well documented and I've already given you the docs where it's explained for pegasos2 as well.

Note that at the moment vo_amiga and pip drivers are not yet completed, scaling support still to be implemented

Task lists can change during interrupt. For example a Signal() in interrupt (for example a replied io request, like timer) can move a task from taskwait list to taskready list.

Btw, how much overhead does the tool itself cause if it relies on quite big number of (soft) interrupts per second (default: docs say 5000, source says 999).

Also the version history in the readme says "Use Forbid() instead of Disable() when reading task lists" which is wrong/bug.

When you see 100% CPU in guest is it possible to find out what code is keeping the CPU busy? That's where we should look to find what's limiting performance.

That's good to know and I do recall something about 3D for 2D operations. Unless I'm thinking of something else. When I upgraded my lite RadeonHD driver to full version it was noticeable the increase in resolution and snappyness on the 5450 I was then using. But, it also has no 3d support, yet it didn't appear to be software rendering.

at least printf, fprintf and sin() are not identical ( newlib.library 53.84 )- calling from SPE code returns nonsence.

And please, how to use soft-float C library?
Is it something like: "gcc -mcrt=clib2 -msoft-float .... -lm" ?

And how is floating-point parameters passed when I used "-mcpu=powerpc -msoft-float" ? Via GPR registers? They are 32-bit in powerpc ABI. Or via stack?

What might however be possible would be to also expose the SPE ABI functions directly through another "main.spe" interface but in order for it to be usable special versions of the startup code and libc will likely also be needed.

I tried to use -lsoft-fp, but it not exists: "ld: cannot find -lsoft-fp"..

For Workbench use what important figure to look at is the G2D rating. Since that would be relevant for 2D compositing.

5. Changing the AmigaOS 4 configuration to use a RadeonRX:
...
You also need to add a line in the Kicklayout file like:
MODULE Kickstart/RadeonRX.chip
Make these changes in the first kickstart configuration, as Uboot does not support RX
cards. So, you won't see anything on the monitor until you reach the start of
AmigaOS 4.
...

...
Improved support for Radeon HD and Radeon RX graphic cards.
Now you can use a Radeon HD / RX via a PCI to PCI Express adapter. On the Sam440ep flex motherboard, it is recommended to use PCI slot #1 for maximum performance. Please note that full support for Radeon RX is still under development and for this reason, with many models of gfx cards, U-Boot does not show any output, but the card works fine once the operating system is loaded.
...

From the QEMU passtrough discussion I am pretty sure that it is the other way around.

The RadeonHD and RadeonRX drivers depend on uboot to init the card before OS4 drivers is loaded.

It looks like the a reason why RX cards are not working with a SAM440 and older systems are because the x86 emulator in their uboot is not capable of running the vbios succesfully.

Since AmigaOS overwrites at least the LTIM bit and we have no evidence that ELCR is used or works on real hardware I think this should be set up by the AmigaOS kernel the way it likes, which Hans seems to also found and tried and said it works so then it's solved.