Stumbled across this, from
Forth Dimensions Vol2 (also
here on Google docs) - page 7.
Bill Powell suggests a scheme of using a single byte for the most frequently used Forth words. He shifts left, then branches on the carry and then optionally on the sign bit. This gives a two-byte coding for a COLON instruction, and a one-byte coding for 64 literals and 64 fast single-byte p-codes.
He summarises thus:
Code:
TINY JSR/RTS DTC ITC
Time overhead 78% 66% 89% 100%
Space required 66% 103% 104% 100%
(By time overhead I think he must mean a time multiplier)
Hope that's a fair rendering of his idea!
Cheers
Ed