Page Comparison

IN:
        DE = (optional) "dynamic" pointer to banner (if banner pointer in definition block is 0)
       BHL = pointer to 7 byte window definition block (if B=0, then local pointer)

           Window Defintion Block offsets:
           0:  A = window ID (bits 0-3). The ID is in range 1-8
               bit 7=1, 6=1: Draw left & right bars, shelf brackets, banner text, bottom line
               bit 7=1, 6=0: Draw left & right bars, shelf brackets, banner text
               bit 7=0, 6=1: Draw left & right bars
               bit 7=0, 6=0: Just create window space (no visible borders)
               bit 5=1: 8 pixel inverted top banner (only evaluated with bit 7=1)
               bit 5=0: 7 pixel inverted top banner (only evaluated with bit 7=1)
               bit 4=1: For all windows: grey screen, then draw window to get a pop-up effect.
           1:  X coordinate (upper left corner) of Window
           2:  Y coordinate (upper left corner) of Window
           3:  WIDTH of Window (inclusive banner & bottom line)
           4:  HEIGHT of Window (inclusive banner & bottom line)
           5:  low byte, high byte address of window banner text
               Only specified if bit 7 of window ID is enabled.
               Set pointer to 0, if using a dynamic bannerbanner 
               (window with different banner each time)

OUT:
     Fc = 0

Registers changed after return:
     A.BCDEHL/IXIY same
     .F....../.... different