INT 13 - IBM/MS INT 13 Extensions - EXTENDED WRITE

	AH = 43h
	AL = write flags
	   ---v1.0,2.0---
	   bit 0: verify write
	   bits 7-1 reserved (0)
	   ---v2.1+ ---
	   00h,01h write without verify
	   02h write with verify
	DL = drive number
	DS:SI -> disk address packet (see #00272)
Return: CF clear if successful
	    AH = 00h
	CF set on error
	    AH = error code (see #00234)
	    disk address packet's block count field set to number of blocks
	      successfully transferred
Note:	the BIOS returns CF set/AH=01h (invalid function) if verify is
	  requested but not supported
SeeAlso: AH=03h,AH=41h"INT 13 Ext",AH=42h"INT 13 Ext",AH=44h