For the PicassoIV it's software.
At first the PIV's Firmware, the PicassoIV.resource, is setting up the Cirrus chip and the cards framebuffer.
The hardware is detecting the Amigas output and the mode it is in. The Firmware reads these values and is setting the corresponding screen mode in the Cirrus CRTC registers. Then it enables the Cirrus capture port that reads the reformated digital Amiga signal directly into the currently shown framebuffer. Thats about it.
Later on Picasso96's PIV driver takes control over the native Screenmode handling through the PIV using the PicassoIV.resource.
I don't really know the procedure for other Amiga graphic cards cause the PIV is a bit special here. But I believe for them it is software controled too.
regs
MastaTabs
