Everything in Oct resides in the {{{NET.COMMON-LISP.OCT}}} package,
with a nickname of {{{OCT}}}. The basic arithmetic operations of
{{{CL}}} are shadowed in this package so you can use natural Lisp
expressions to operate on quad-doubles. Special functions are
included.

There are two types added:

 QD-REAL::
   A quad-double type. This has about 65 digits of precision, or about
   212 bits.
 QD-COMPLEX::
   A complex type consisting of two {{{QD-REAL}}} values.

The reader is also modified to make it easier to enter quad-double
values. To enable the reader, bind {{{*readtable*}}} to
{{{oct::*oct-readtable*}}}.  {{{#q}}} is used to enter both
{{{QD-REAL}}} and {{{QD-COMPLEX}}} types. For example {{{#q1.25q5}}}
is the {{{QD-REAL}}} with the value {{{125000}}}. The exponent marker
is {{{q}}}. To enter a {{{QD-COMPLEX}}} value, use {{{#q(r i)}}} where
{{{r}}} and {{{i}}} are the real and imaginary parts. The parts will
be coerced to {{{QD-REAL}}} type if necessary.

Here are a few examples of using {{{OCT}}}:

{{{
  CL-USER (in-package "QD")
  QD> (/ (sqrt #q3) 2)
  #q0.866025403784438646763723170752936183471402626905190314027903489696q0
  QD> (sin (/ +pi+ 3))
  #q0.86602540378443864676372317075293618347140262690519031402790348972q0
  QD> (sqrt #q-1)
  #q(#q0.0q0 #q1.0q0)
  QD> (coerce 7 'qd-complex)
  #q(#q7.0q0 #q0.0q0)
  QD> (integer-decode-float +pi+)
  165424160919322423196824703508232170249081435635340508251270944637
  -215
  1
  QD> +pi+
  #q3.1415926535897932384626433832795028841971693993751058209749445923q0
  QD> (* 4 (atan #q1))
  #q3.1415926535897932384626433832795028841971693993751058209749445923q0
}}} 

Note that {{{+pi+}}} is the {{{QD-REAL}}} value for pi.