The key C-M-q runs
fortran-indent-subprogram, a command
to reindent all the lines of the Fortran subprogram (function or
subroutine) containing point.
The key C-M-j runs
fortran-split-line, which splits
a line in the appropriate fashion for Fortran. In a non-comment line,
the second half becomes a continuation line and is indented
accordingly. In a comment line, both halves become separate comment
M-^ or C-c C-d run the command
which joins a continuation line back to the previous line, roughly as
the inverse of
fortran-split-line. The point must be on a
continuation line when this command is invoked.
M-q in Fortran mode fills the comment block or statement that point is in. This removes any excess statement continuations.