CLI - Clear Interrupt Flag (disable)

	Usage:	CLI
	Modifies flags: IF


	Disables the maskable hardware interrupts by clearing the Interrupt
	flag.  NMI's and software interrupts are not inhibited.


				 Clocks			Size
	Operands	 808x  286   386   486		Bytes

	none		  2	2     3	    5		  1


	- see Instruction Timing