Interrupt 67h	Expanded Memory Specification
Function  6Ah	System Map Functions
SubFunc   02h	Swap System Map
entry	AH	6Ah
	AL	02h
	CH	First Window
	CL	Window Count
	DS:SI	Pointer to next page map array
	ES:DI	Pointer to empty page map array
return  AH      status (see Int\67f\40)
		00h	Function Successful
		ES:DI	Pointer to previous page map array