[SeaBIOS] [PATCH 5/6] sercon: split-output implementation

[Gerd Hoffmann]

> On SeaVGABIOS, text writing now works in all graphic modes, though
> not
> all vgabios support that.  The original bochs vgabios didn't support
> it in "direct" or "packed" modes, and I think it was broken for years
> in planar mode.  So, it's rare for text writing to be seen in any
> mode
> above 7.  (It's also rare for anything to go into cga mode today, but
> for ancient programs, it would not have been unusual to write out
> text
> in cga mode.)

Ah, ok.  Didn't know that.  So it actually makes sense to support all
modes <= 7 in sercon.  4+5 are 320x200, which should be 40x25 chars,
and 6 is 640x200 and therefore 80x25 chars (both using 8x8 font).  I'll
go add 4+5+6 and simplify the mode number checks.

cheers,
  Gerd