WinUAE technical questions.

[kamelito]

Hi Toni,
I would like to know at which exact pixel location WinUAE does throw the VBL IRQ and at which exact pixel location does it reload the Copper list?
cheers

[ross]

This question is not WinUAE related but chipset related

Copper jump to COP1LT when Agnus vertical counter reset to 0 value (so the position [0,0]).
VBI trigger at VBSTRT, that's hardwired at line 0 for Fat Agnus and line 1 for A1000 Agnus.

So coincidentally both usually start at the same time (the copper is usually faster than the CPU and therefore manages to execute its instructions first).

[Toni Wilen]

Why pixel? Internally it is based on CCKs, not pixels (Only Denise is "pixel based") Check DMA debugger first line (v-1 to enable (-1 = no overlay), exit and enter debugger, v 0)

Copper reload is triggered at cycle 2 (always line 0), copper does first DMA read during cycle 4 (but this read is from previous address), first copper DMA read from start of copper list: cycle 6.

Vblank is triggered at cycle 3 (first refresh slot = horizontal strobe which Paula uses to generate vblank interrupt), it also takes 2 more cycles before CPU sees it. (and as ross said, line depends on Agnus version, A1000 is special case)

Copper jump to COP1LT when Agnus vertical counter reset to 0 value (so the position [0,0]).

No. Not exactly horizontal or vertical zero or both.

Did you forget that we did run tests just today that needed this to be exactly correct

[ross]

I oversimplified to keep it simple

[Toni Wilen]

Originally Posted by ross

I oversimplified to keep it simple

Yes but OP wanted pixel perfect answer

At least CCK can be converted to exact pixels.

EDIT: if you want to see where first copper color write can happen, latest winuae.7z + display panel "ultra extreme debug" overscan mode can show it. (It disables all blanking and shows full raster area)

[ross]

Originally Posted by Toni Wilen

Yes but OP wanted pixel perfect answer

At least CCK can be converted to exact pixels.

Right.

Then we also add that the position of the VBI could be on any line and more times in the same frame with ECS+

[ross]

Originally Posted by kamelito

I would like to know at which exact pixel location WinUAE does throw the VBL IRQ and at which exact pixel location does it reload the Copper list?

But to go back on track, why do you need this precise data?

Usually you don't need to be 'pixel exact' (even if in this case it is not the proper terminology, the pixels are not even usually visible in that area), but to have an idea for when the two events occur (generally: at the beginning of the frame), in order to organize your code.

Maybe with some more information you will have answers that best suit your needs.