Mail Archives: djgpp/1998/10/29/07:55:09
On Thu, 29 Oct 1998, Ludvig Larsson wrote:
> Hope someone can help me with a figure or two(I'v read some time
> ago that a bankswitch eats a houndred or so processor cycles?).
Really don't know the exact speed, but here are the facts;
BankedVBE1.2: for each bank (640x480x8 = 6banks) do: switch to rmode
(real slow), call VESA interrupt (depends of how poor the
code is), and switch back to pmode (slow too).
BankedVBE2: for each bank do: call VESA service routine. Faster than
previous, but still depends a lot of how good VESA routines are.
LFB: Just write to display memory all that is needed. No slow-down
vesa-calls or such.
From my experience:
I myself have a P200 with ET6000-based VBE2-display. When I ran the
bank-switching mode in another P200 with S3-based VBE1.2, speed was
reduced by some 30-50% ... In my own computer the performance loss
when using banks is almost unnoticeable, though.
/// Toni Räsänen
/// torasane AT mail DOT student DOT oulu DOT fi
- Raw text -