Page Comparison

IN:
     A = window ID (ASCII '1' - '8') or A = 0 for current window
     BC = NQ_WBOX
OUT:
     A = window id (ASCII '1' to '8')
     C = width
     B = depth
     E = offset from left of screen (always 0)
     D = offset from top of screen (always 0)

Registers changed after return:
     ......../IXIY same
     AFBCDEHL/.... different

IN:
     A = window ID (ASCII '1' - '8') or A = 0 for current window
     BC = NQ_WCUR
OUT:
     A = window ID (ASCII '1' to '8')
     C = x coordinate of cursor
     B = y coordinate of cursor
     D = bit 7 set if cursor is ON

Registers changed after return:
     ......../IXIY same
     AFBCDEHL/.... different

IN:
     BC = NQ_RDS
     DE = pointer to a buffer to store text
     HL = number of bytes to read
OUT:
     -

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