INT 10,0 - Set Video Mode

	AH = 00
	AL = 00  40x25 B/W text (CGA,EGA,MCGA,VGA)
	   = 01  40x25 16 color text (CGA,EGA,MCGA,VGA)
	   = 02  80x25 16 shades of gray text (CGA,EGA,MCGA,VGA)
	   = 03  80x25 16 color text (CGA,EGA,MCGA,VGA)
	   = 04  320x200 4 color graphics (CGA,EGA,MCGA,VGA)
	   = 05  320x200 4 color graphics (CGA,EGA,MCGA,VGA)
	   = 06  640x200 B/W graphics (CGA,EGA,MCGA,VGA)
	   = 07  80x25 Monochrome text (MDA,HERC,EGA,VGA)
	   = 08  160x200 16 color graphics (PCjr)
	   = 09  320x200 16 color graphics (PCjr)
	   = 0A  640x200 4 color graphics (PCjr)
	   = 0B  Reserved (EGA BIOS function 11)
	   = 0C  Reserved (EGA BIOS function 11)
	   = 0D  320x200 16 color graphics (EGA,VGA)
	   = 0E  640x200 16 color graphics (EGA,VGA)
	   = 0F  640x350 Monochrome graphics (EGA,VGA)
	   = 10  640x350 16 color graphics (EGA or VGA with 128K)
		 640x350 4 color graphics (64K EGA)
	   = 11  640x480 B/W graphics (MCGA,VGA)
	   = 12  640x480 16 color graphics (VGA)
	   = 13  320x200 256 color graphics (MCGA,VGA)
	   = 8x  EGA, MCGA or VGA ignore bit 7, see below
	   = 9x  EGA, MCGA or VGA ignore bit 7, see below


	- if AL bit 7=1, prevents EGA,MCGA & VGA from clearing display
	- function updates byte at 40:49;  bit 7 of byte 40:87
	  (EGA/VGA Display Data Area) is set to the value of AL bit 7