🚀 go-pugleaf

There is a bug in the implementation of the 11/44 float box.  It
affects only the stexp instruction (as far as I've been able to
discover).  The problem is that when you use auto-increment or
-decrement as the destination mode, the register gets changed by
the current size of the float word, NOT by 2.

This causes havoc if you do it to the sp, for instance.

That actual code doesn't occur in v7 anywhere; it was discovered
when I ported fc to v7 (we needed it for our 11/60 satellite sys-
tem).

This has been reported to DEC, but no action has been taken.