* bignum.c (maxpow_in_bdigit_dbl): Use tables if available.
  (maxpow_in_bdigit): Ditto.
  (U16): New macro.
  (U32): Ditto.
  (U64): Ditto.
  (U128): Ditto.
  (maxpow16_exp): New table.
  (maxpow16_num): New table.
  (maxpow32_exp): New table.
  (maxpow32_num): New table.
  (maxpow64_exp): New table.
  (maxpow64_num): New table.
  (maxpow128_exp): New table.
  (maxpow128_num): New table.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41773 b2dd03c8-39d4-4d8f-98ff-823fe69b080e