P register indexing

[Alejandro Paz(Germany)]

I was wondering just why did they use these schemes ? Did they do it because they published the code for the 45 and then they didn't wanted people fiddling with the next calcs, or there is any savings in terms of gates ?
The Nut processor has also a similar encoding, but only one encoding instead of the two used by the Woodstock processor. Such an encoding is not used in the Saturn. But the Saturn was a kind of open architecture after all.