!
! The first 512 bytes of page 0 are hardware defined. (See Princs of Op)
! EMAS defines some addition locations for convenience
!
!     X200 (512)                        Soft crash psw Set by G-C.
!     X208 (520)                        System Program error psw.
!                                       Set by G-C as the New PE psw and
!                                       copied to here by L-C when its sets
!                                       the User PE psw to 104.
!     X210 (528)                        The local cpu timer PSW. Set
!                                       by L-C and used by G-C when clock interrupt
!                                       is due to cpu timer exceeded.
!     X218 (536)                        Local controller initial activate
!                                       PSW. Set by G-C
!     X220 (544)                        Local Contoller exit PSW. Set by G-C
!                                       for fast return.
!     X228 (552)                        (Copy of) Restart PSW set ny ENTER
!     X230 (560)                        Top of store marker for dump program
!     X238-X27f (568-639)               unused
!     X280-X2bf (640-703)               G-C context(16 regs) actaully only
!                                       5-14 need to be reloaded
!     X2C0 -X2ff (704-767)              G-C control registers dumped here
!
!     X800 (2048)                       Temporary dump area for Global ints
!     X900 (2304)                       Temporary dump area for local ints
!      xA00-xA10                        Restart sequence for 2nd (&3rd etc) OCPs
!
!     rest undefined
!
!     N.B. G-C = Global Controller.  L-C = Local Controller
!