Alter Page Map and Call (cross page Call)                   
  
    | 
       Input  | 
    
       Output  | 
   
  
    | 
       AX  | 
    56h | 
    Type Code | 
    Error
      Code | 
      | 
    AX | 
   
  
    | 
       BX  | 
      | 
      | 
      | 
      | 
    BX | 
   
  
    | 
       DX  | 
     EMM
      Handle | 
      | 
      | 
    CX | 
   
  
    | 
       DS:SI  | 
     Ptr
      to Page Map and Call Addr | 
      | 
      | 
    DX | 
   
 Type Code: 00h = Physical Page Number
           01h = Segment Address
     This  subfunction saves the current memory mapping  context,
     alters  the specified memory mapping context, and  transfers
     control to the specified address.
     Notes:
     *  Flags  and  all  registers except AX are  preserved  to  the
        called routine. On return, flags and all registers except AX
        are preserved; AL is set to zero and AX is undefined.
     *  Values in registers  which don't contain required parameters
        maintain the values across the call. The values in registers
        (with  the  exception  of AX) and  the  flag  state  at  the
        beginning of the function are  still  in  the  registers and
        flags when the target address is reached.
     *  Developers  using this subfunction must make allowances  for
        the additional stack space this subfunction will use. |