Looking for a documentation package for old Fortran code

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FORTRAN

I am retired, but for MANY years designed, developed and maintained software for process control real time applications.

Is there a package available that would read as input old Fortran Source code and create a visual flowchart output that could then be used by newer programmers as a starting point to develop code on a newer hardware platform?

I am an old programmer who could read the old code and manually create flowcharts and a written description [I have done this several times in the past], but I was thinking there might be a package or program out there that mechanizes most of it.

If there is such a package, if it also allowed for manual modification of the generated flowchart file[s] after they are created, it could be used to move a control system from old hardware to newer hardware much faster and easier, with programmers adept on their new computer control system.

Thank you for any comments or references.

What I have tried:

Have tried looking for something like this, but did not find anything yet that inputs old Fortran code and produces a flowchart as output.