I've compiled my first kernel and tried fixing fpu_fscale.c and it makes my
test program work OK.  I think there are at least three places where the
variable scale isn't set properly in the fscale code.  I'll need to write
some test programs for each case.  GhostScript still has problems though. 
It can now print boxes OK but text still doesn't appear at all.  (This is
what I saw when I bypassed the fscale optimisation in the source code.) 
I'm no expert in floating point arithmetic systems but I'll keep digging to
see what I can find out.

Norman