6.6.2 Floating point stack

fdrop ( r – ) floating “f-drop”
fnip ( r1 r2 – r2 ) gforth-0.2 “f-nip”
fdup ( r – r r ) floating “f-dupe”
fover ( r1 r2 – r1 r2 r1 ) floating “f-over”
fthird ( r1 r2 r3 – r1 r2 r3 r1 ) gforth-1.0 “fthird”
ffourth ( r1 r2 r3 r4 – r1 r2 r3 r4 r1 ) gforth-1.0 “ffourth”
fswap ( r1 r2 – r2 r1 ) floating “f-swap”
frot ( r1 r2 r3 – r2 r3 r1 ) floating “f-rote”
f-rot ( r1 r2 r3 – r3 r1 r2 ) floating “f-not-rote”
ftuck ( r1 r2 – r2 r1 r2 ) gforth-0.2 “f-tuck”
fpick ( f:... u – f:... r ) gforth-0.4 “fpick”

Actually the stack effect is r0 ... ru u -- r0 ... ru r0 .