Privileged routines manipulate privileged hardware registers.

1  –  MFPR

  The MFPR function returns an unsigned value that is the value of
  a VAX internal processor register.

  Syntax:

     MFPR( ipr_register_expression )

  The  'ipr_register_expression'  parameter   is   an   expression
  compatible with the UNSIGNED type.

  The HP Pascal compiler generates user-mode code.  HP Pascal does
  not  explicitly support the running of VSI Pascal generated code
  in kernel mode.  However, if the following rules  are  observed,
  then the generated code has a good chance of working as expected
  in elevated access modes:

   o  All code must be compiled with  the  /NOCHECK  qualifier  or
      [CHECK(NONE)]  attribute.   The  HP  Pascal  on  OpenVMS VAX
      run-time signaling method relies on trying  to  execute  the
      HALT  instruction.   In  user-mode, this causes an exception
      that is a signal to the  HP  Pascal  run-time  library.   In
      kernel-mode  on an OpenVMS VAX system, this simply HALTs the
      machine.

   o  Avoid  all  routine  calls  which  translate  into  Run-Time
      Library  calls.   These  include  all  I/O routines, several
      arithmetic routines, several string routines, etc.

2  –  MTPR

  The MTPR procedure assigns a value into a VAX internal processor
  register.

  Syntax:

     MTPR( ipr_register_expression, source_expression );

  The 'ipr_register_expression' and 'source_expression' parameters
  are  expressions  compatible  with the unsigned type.  HP Pascal
  stores the  value  specified  by  'source-expression'  into  the
  internal       processor       register       specified       by
  'ipr-register-expression'.

  The HP Pascal compiler generates user-mode code.  HP Pascal does
  not  explicitly  support the running of HP Pascal generated code
  in kernel mode.  However, if the following rules  are  observed,
  then the generated code has a good chance of working as expected
  in elevated access modes:

   o  All code must be compiled with  the  /NOCHECK  qualifier  or
      [CHECK(NONE)]  attribute.   The  HP  Pascal  for OpenVMS VAX
      systems  run-time  signaling  method  relies  on  trying  to
      execute  the HALT instruction.  In user-mode, this causes an
      exception which is  a  signal  to  the  HP  Pascal  run-time
      library.   In  kernel-mode  on  an  OpenVMS VAX system, this
      simply HALTs the machine.

   o  Avoid  all  routine  calls  which  translate  into  Run-Time
      Library  calls.   These  include  all  I/O routines, several
      arithmetic routines, several string routines, etc.