INT 62 u - FGDRIVER v4.02 - "FG_SCROLL" - VERTICALLY SCROLL SCREEN REGION
	AX = 00A5h
	BX = left edge column
	CX = right edge column
	DX = top edge row
	SI = bottom edge row
	DI = number of pixels by which to scroll (positive scrolls up,
	      negative scrolls down)
	ES = type of scroll
	    0000h circular (rows scrolled off are copied to vacated rows)
	    else vacated rows are filled with the current color
Notes:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474 at AX=0000h)
	In graphics modes, the left and right edges are adjusted to byte
	  boundaries if necessary
	Circular scrolling uses part of the hidden page as a workspace
SeeAlso: AX=0088h,AX=00B2h