find_root with bfloats



Hi,

I am experimenting with converting find_root to use bfloats. 
  I am taking a very naive (some might say quick and dirty) 
approach for the moment.

I changed the constants at the beginning of  intpol.lisp to 
bfloats, the two occurrences of $float to $bfloat, but now I 
am left with two instances of coerce-float-fun.  This does 
not appear to have a straightforward bfloat analogue.

Is this perhaps what makes the conversion not so easy?

					Kostas