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5.6.2 Floating point stack

Whilst every sane Forth has a separate floating-point stack, it is not strictly required; an ANS Forth system could theoretically keep floating-point numbers on the data stack. As an additional difficulty, you don't know how many cells a floating-point number takes. It is reportedly possible to write words in a way that they work also for a unified stack model, but we do not recommend trying it. Instead, just say that your program has an environmental dependency on a separate floating-point stack.

floating-stack       – n         environment       “floating-stack”

n is non-zero, showing that Gforth maintains a separate floating-point stack of depth n.

fdrop       r –        float       “f-drop”

fnip       r1 r2 – r2        gforth       “f-nip”

fdup       r – r r        float       “f-dupe”

fover       r1 r2 – r1 r2 r1        float       “f-over”

ftuck       r1 r2 – r2 r1 r2        gforth       “f-tuck”

fswap       r1 r2 – r2 r1        float       “f-swap”

fpick       f:... u – f:... r        gforth       “fpick”

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

frot       r1 r2 r3 – r2 r3 r1        float       “f-rote”