AH = 00h: Set Video Mode

This function sets the display mode. The new mode is determined by the value passed in the AL register.

• Input: AH = 00h
  AL = MODE (see below)

  00h = Text, 40x25, 16x8 char, B&W
  01h = Text, 40x25, 16x8 char, Color
  02h = Text, 80x25, 8x8 char, B&W
  03h = Text, 80x25, 8x8 char, Color
  04h = Graphics, 320x200, Std. char 16x8, Color
  05h = Graphics, 320x200, Std. char 16x8, B&W
  06h = Graphics, 640x200, Std. char 8x8, B&W (MDA)
  07h = Text, 40x16 HP95LX, 16x12 char, B&W Zoom into 80x25(MDA)
  20h = Graphics, 240x128 HP95LX, 12x8 char, B&W (MDA)
  21h = Text, 80x25, 8x8 char, B&W
  80h = Text, 64x18, 10x11 char, B&W Zoom into 80x25
  82h = Text, 40x25, 16x8 char, B&W Zoom into 80x25
  84h = Text, 40x16, 16x12 char, B&W Zoom into 80x25
  81h = Text, 64x18, 10x11 char, Color Zoom into 80x25
  83h = Text, 40x25, 16x8 char, Color Zoom into 80x25
  85h = Text, 40x16, 16x12 char, Color Zoom into 80x25
  

• Output: None
• Error conditions: None
• Registers modified: AX
• The mode is changed in the BIOS and hardware.
• The screen is cleared as a side effect of changing the mode.
• If the mode is Text, the font loader is called to load 8x8, 16x12, and 10x11 fonts in the current code page.
• See BIOS Int 10h, function D0h for zoom switching.
• The value stored in the BIOS RAM Variable "CRTMODE" will be 0-7, or 20h.