AH = 07h: Scroll Window Down

This function scrolls the contents of a specified window in the display down a specified number of lines. Text that is scrolled beyond the bottom of the window is lost. The new lines that appear at the top of the window are filled with blanks having the specified attribute. As a special case, this routine may be used to initialize a rectangular section of the display to all blanks with a specified attribute. In text modes that support multiple pages, this function affects only the page currently being displayed. The window is specified by providing the row and column addresses of the upper left and lower right corners. The video mode may be either Text or Graphics. The number of lines to be scrolled is passed in AL.

• Input: AH = 07h
  AL = Number of lines to scroll (0 = blanks entire scroll area)
  BH = Attribute of blanked lines (alpha mode) or Fill character for blanked lines (graphics mode)
  CH = Row address of character in upper left corner of window
  CL = Column address of character in upper left corner of window
  DH = Row address of character in lower right corner of window
  DL = Column address of character in lower right corner of window
  

• Output: None
• Error conditions: None
• Registers modified: AX