Quoting :doc note-6-5 (this improves upon a fix reported in a previous
version of this paragraph):

  (Allegro CL only) We fixed a bug in function [princ$] when invoked in
  an ACL2 image with Allegro CL as the host Lisp implementation. When
  printing a complex number in base 16, lower case characters were
  produced, for example printing #C(c d) instead of the characters
  predicted by the axioms, namely #C(C D), Thanks to Jared Davis for
  bringing this bug to our attention, and also to pointing out
  excessive printing of a big note about such printing. We now avoid
  that note altogether, which had warned that printing numbers in
  base 16 can be slow for Allegro CL. In fact, that performance issue
  has been eliminated: for example, after evaluating (defconst *c*
  (expt 2 200000)) and (set-print-base 16 state), the form (time$
  (pprogn (princ$ *c* *standard-co* state) state)) reports taking
  about 3 seconds before the change but about 1/100 seconds after the
  change. Thanks to David Margolies of Franz Inc. for passing along a
  remark from a colleague that showed how to make this improvement.


git-svn-id: http://acl2-devel.googlecode.com/svn/trunk@1304 5d84a466-a78b-0930-a311-59b22171a541