( -- ) ( F: r -- ) or ( r -- )

Display, with a trailing space, the top number on the floating-point stack using engineering notation, where the significand is greater than or equal to 1.0 and less than 1000.0 and the decimal exponent is a multiple of three.

An ambiguous condition exists if the value of BASE is not (decimal) ten or if the character string representation exceeds the size of the pictured numeric output string buffer.