             NDP_OFF / NDP_ON / NDP_STAT

    Programs to control co-processor for Windows

        Copyright  1994, UK, John M.Howells
    The programs are freeware, and may be freely

        distributed for non-profit purposes.
                          
When  running Windows a co-processor (NDP -  Numeric
Data  Processor)  will be used if  one  is  present.
However,  sometimes it is necessary to test software
on a system that is equipped with a co-processor but
without  using it, to check that everything  behaves
as it should and to get some idea of the performance
difference.

Fortunately  Windows (at least  up  to  Windows  for
Workgroups 3.11) does not perform its own  test  for
the  presence of a co-processor, but relies  on  the
BIOS  equipment word. This may seem a little  naive,
but  it  works  in  our favour, as  to  perform  the
testing  required it is only necessary to clear  the
appropriate bit before starting Windows.

The programs in this package provide that function.

     NDP_OFF   disables Windows use of the  co-
               processor by clearing  the  BIOS
               co-processor bit.
     
     NDP_ON    enables  Windows use of the  co-
               processor by setting the BIOS co-
               processor bit.
     
     NDP_STAT  reports  the state  of  the  co-
               processor bit.

In  each  case  the  program works  only  if  a  co-
processor  is present (and the check for  this  does
not  rely on the BIOS equipped bit), and works  only
if Windows or another Task Switcher is not running.

Note  that the Borland C++ standard run-time library
for DOS also recognizes this bit, and does not use a
co-processor  if  the bit is cleared.  However,  the
Microsoft  Visual C++ run-time library  uses  a  co-
processor regardless of the setting of the bit.

John M.Howells, Wigan, UK
CIS ID: 100031,353
10th May, 1994
