Int 31 Fn 0604  P - DPMI 0.9+ - Get Page Size                              [E]

   AX = 0604h

Return: CF clear if successful
       BX:CX = page size in bytes
   CF set on error
       AX = error code (DPMI 1.0+)
       8001h unsupported, 16-bit host
BUG:   the Borland C++ 3.1 DPMILOAD returns with CF clear but BX and CX
     unchanged