WBINVD - Write-Back and Invalidate Cache

	Usage:	WBINVD
	Modifies flags: None


	Flushes internal cache, then signals the external cache to write
	back current data followed by a signal to flush the external cache.

				 Clocks			Size
	Operands	 808x  286   386   486		Bytes

	none		  -	-     -     5		  2


	- see Instruction Timing