INT 67,48 - Restore Page Map Context (LIM EMS 3.0+)

	AH = 48h
	DX = EMM handle assigned to the interrupt service routine
	     servicing the interrupt

	on return:
	AH = 00  success
	   = error code (see EMS STATUS)

	- any TSR, ISR or device driver using EMS should save contexts
	  before manipulating EMS memory and restore contexts afterwards
	- registers not listed are preserved