INT 16,12 - Extended Get Keyboard Status (AT+)

	AH = 12h

	on return:
	AH = BIOS keyboard flags (BIOS Data Area location 40:18)

		|7|6|5|4|3|2|1|0|  AH
		 | | | | | | | `---- left CTRL key depressed
		 | | | | | | `----- left ALT key depressed
		 | | | | | `------ right CTRL key pressed
		 | | | | `------- right ALT key depressed
		 | | | `-------- scroll-lock depressed
		 | | `--------- num-lock key depressed
		 | `---------- caps-lock key depressed
		 `----------- system request key depressed

	AL = BIOS keyboard flags (BIOS Data Area location 40:17)

		|7|6|5|4|3|2|1|0|  AL
		 | | | | | | | `---- right shift key depressed
		 | | | | | | `----- left shift key depressed
		 | | | | | `------ CTRL key depressed
		 | | | | `------- ALT key depressed
		 | | | `-------- scroll-lock is active
		 | | `--------- num-lock is active
		 | `---------- caps-lock is active
		 `----------- insert is active


	- available on AT and PS/2 machines with extended keyboard support
	- similar to INT 16,2

	- see	KB FLAGS