)
Values Windows support procedure called with:
	BP = function
	    0001h Get ECB
		BX = socket number
		Return: ES:SI -> ECB or 0000h:0000h if none available
	    0002h Count Listen ECBs
		AX = BX = socket
		Return: CX = number of listen ECBs for socket
				(must be >= 2 for SPX to work)
	    0003h ???
	    0004h Inform task switcher of ECB locations
		Note:	registers other than those listed above are equal
			  to the values when IPX was called
Note:	the support function will not be called if IPX is called with BX
	  bit 15 set