Uses the "big multiplication table" in 64KB of extended memory if
bank switching appears to work, otherwise uses the table of squares
lookups.
Initial view clocks in at 13.133 ms/px for the XE version and still
14.211 ms/px for the 400/800/XL version.
Tested in emulator with 130XE and XL+Ultimate 1MB upgrade configs,
and base implementation on the 800XL emulator.
planning to try a 64KB table of 8x7-bit multiplies in the high memory
on a 130XE or other high-memory-capable machine
not yet working or finished
too many cycles of overhead per invocation
