Int 62 Fn 0047 u - Fgdriver V4.02 - "fg_getlines" - Get Text Rows For Cu [V]
AX = 0047h
Return: AX = number of text rows on screen in current video mode
Note: the FGDRIVER functions are rearranged with each major release, but
their parameters do not change (see #3145 at AX=0000h)
See Also: AX=00AFh,AX=00C2h