Format of AERASE parameter block:
Offset	Size	Description	)
 00h	WORD	0005h (length of following data)
 02h	BYTE	left-most column (0-based)
 03h	BYTE	top-most row (0-based)
 04h	BYTE	rectangle's width in character cells
 05h	BYTE	rectangle's height in character cells
 06h	BYTE	background color (bits 7-4)
SeeAlso: #03884