On Wed, 25 Aug 1999, Hilary Cheng wrote:
> Hi all,
>
> >Hi all
> >
> >I updated the vga driver, made some bugfixes, added a stop routine that
> >switches to the previous video mode and a bitblt to draw sprites (I hate
> >bit shiftings *g*). Found 2 bugs in the jvm -> idiv and irem.
>
> Would u mind send me the latest code ? :D
yep, but first I have to clean up...
> I wanna to test ur bitblt function and I would like to implement it to
> draw Font on the VGA Screen.
cool, do you read the fonts from the vid-mem? the start routine
clears unforunately the hole vid-mem, so no fonts after the stop routine
are available (yet).
> Also, I have finished a drawLine and drawRect routine. These two methods
> are similar to java.awt.Graphcis. I will try to implements some more
> java.awt.Graphisc
> in device driver level.
hmm, does drawLine and drawRect write direct to the vidmem or is there a
kind of a virtual screen (jdkxx?).
(drawRect/drawLine/drawString->buffer->bitblt?->vidmem) or
(drawRect/drawLine/drawString->vidmem)
If there is a kind of a buffer, then we can't use the drawLine and
drawRect which is implemented in the driver. But I really don't know!
> >I will update (send code to John-> still no cvs access) the code when
> >the general driver implementation is done (end of this week, I guess).
> >
> >The problem is the speed: I think we (Hilary?, you have done something
> >similar) should implement a native memcopy to speed up the vga output.
>
> Well, I found two bugs in JVM.
> 1. Date Object -- When I create Date Object, JJOS Kernel will got some
> behaivour. (Show lots of Zero on the screen.)
I had the same bug, but it was a div by zero. This is now fixed.
->idiv,irem, already sent to John.
> 2. String -- String can't perform chatAt and getBytes, toCharArray
> So I can't draw Character on VGA from a Java String.
>
> I have implemented a simple fill routine. It just fill up a memory space
> in native implementation. But I think this routine is just for testing
> puporse. If speed of JJOS is fast enough, It will be deleted.
>
> >vga and speed:
> >To avoid flickering, you have to write into the vga-mem when the vertical
> >retrace is active. the memcopy should be finished before the vertical
> >retrace ends. If not, you will see the sprite flickering. The current
> >speed of the write8/16/32 is to slow to finish before the vertical retrace
> >gets inactive.
[cut]
Thomas Bocek
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