Re: CVS updates/VGA mode setting

[Petr V. <VAN...@vc...>]

On 31 Aug 00 at 23:01, Vojtech Pavlik wrote:
> On Thu, Aug 31, 2000 at 06:36:08PM +0000, Petr Vandrovec wrote:
> 
> > If you want to support only standard modes (text, cfb8, vgaplanes, 
> > vga8planes), it is easy. But there is couple of more or less nonstandard
> > modes too. 2 (1plane) or 4-color (2planes) modes, alphanumeric mode with
> > character generator disabled (gives you `spectrum like' attribute + 8pixels).
> > What to do with them? Let them fall through and report something similar
> > for them?
> 
> The 1-line font (which you describe as spectrum-like) actually could be
> quite useful for having a huge font, while still keeping minimum video
> memory size.

Problem is that standard VGA can use only 64KB (VGA text compat.),
or 128KB (when VGA hardware in real 4plane mode) in that mode, as planes
2 & 3 are reserved for character generator and unused... This
limits you to either 80x409 (~ 640x409) or 80x819 (or 100x655 (~800x655))... 
This is not too much - it is same as 4plane modes (real textmode with
8x16 font gives you virtual screen 640x6544, BTW).

And unfortunately, although bmove works on same speed as in 4plane mode,
putc/putcs are much slower, as you cannot use special VGA write modes :-(
16 writes in 128KB mode, instead of 8 for 4plane...
                                                 Best regards,
                                                    Petr Vandrovec
                                                    van...@vc...