INT 21 - Phar Lap 386/DOS-Extender v2.1c+ - GET INFO ON DOS DATA BUFFER

	AX = 2517h
Return: CF clear
	ES:EBX -> data buffer (protected mode address)
	ECX -> data buffer (real mode address)
	EDX = size of data buffer in bytes
Note:	the data buffer's address changes after calls to AX=2512h and AX=252Ah
SeeAlso: AX=2512h,AX=252Ah,AX=2530h