Yes, and it *is* floating point.
Is there an artucle that explains how blend, histogram and other operations are handled?
they are handled In the same way but in a linear version of the color space which makes a big difference. Search and learn about linear vs non - linear editing.
here's one link about it. http://mysite.verizon.net/spitzak/conversion/index.html
when reading the information in the above link have in mind that although the author talks about sRGB this is valid for all RGB color spaces which have non-linear gamma.
So once an image is 32bpc, the processing is linear. ACR doesn't offer 32bpc now. Will it in some time soon?
I'm well aware of the linear/non-linear processing difference as my plugins do what is proper when I get the data internally and in FP.