The ORTH fingerprint is designed to ease transition between the Orthogonal programming language and Befunge-98 (or higher dimension Funges.) Even if transition from Orthogonal is not an issue, the ORTH library contains some potentially interesting instructions not in standard Funge-98.
After successfully loading ORTH, the instructions A, E, G, O, P, S, V, W, X, Y, and Z take on new semantics. The following table, which can be used to translate Orthogonal to Funge-98 and back, includes which Orthogonal instructions they emulate:
Funge Orthogonal Semantic + + add * * multiply - - subtract / / divide % % modulo (positive values only) >>> A & bitwise AND >>> O | bitwise OR >>> E ^ bitwise EXOR ! ! logical negate \ ~ swap : @ duplicate $ $ pop < L go west > H go east ^ K go north v J go south ] cw rotate right [ ccw rotate left r rev reverse >>> X x change x >>> Y y change y >>> V dx change dx >>> W dy change dy >>> G = ortho get >>> P # ortho put >>> Z ? ramp if zero , c output character >>> S s output string . d output decimal z nop no operation q ret quit