Example:
using 1
mov R1,AR0
means
mov R1,8
An equivalent for the upper bytes would be like
mov R1H,AR0H1.
There are 2 "banked"/shared SFRs, R0H and R1H, and 4 sets of the "real" SFRs, ARiHj, i={0,1}, j={0,3}. The hw is mirroring the ARiHj into RiH according to the current bank set (j). Altogether 10 SFR positions.
However, I don't think direct access to ARiHj is necessary, so in case of SFR space shortage they can be hidden into some SFR-banking scheme, or buried completely.

As per compatibility, consider this "legacy" code:
CheckLongZero:
clr a
mov r2,#4
loop:
orl a,@r0
inc r0
djnz r2,loop
ret
With the "high-in-SFR" scheme this still works, with "r0r2" scheme not.
Please don't elaborate, I know this may or may not be relevant.

As per KICI, I guess I stands for Intelligent or Ingenious, but as well may be Impossible or Idiotic or... :-)

Jan Waclawek

PS Re buying power: let's make a 8052.com syndicate. I will bet a 2-month salary (~$1000). If 100 of the users will (some earn more, some less), that's $100k. If we can negotiate $1/piece (???), maybe 100kpcs is worth considering for a manufaturer to think about it. I bet I can sell my share of 1kpcs quite easily.

Brother of Morpheus was called Phantasos... :-)