RE: [stella] end of frame??

Subject: RE: [stella] end of frame??
From: Nicolás Olhaberry <nolh@xxxxxxxxxxxxx>
Date: Wed, 31 Oct 2001 17:08:47 -0300
----- Original Message -----
From: ben <ben@xxxxxxxx>
To: <stella@xxxxxxxxxxx>
Sent: Wednesday, October 31, 2001 12:11 PM
Subject: [stella] end of frame??

> Hi,


> As I understand it, the beam does not return without a VSYNC.  But, is it
> common for coders to let the beam sit at the end of the frame for a while
> before executing a VSYNC?  I have seen the bahaviour below quite a bit
> while writing my emulator:

It is very common, atari hasn´t followed his own guidelines from his very
first game ;-)

> Enlightenment Please?  What am I missing? :)  You'll notice that all I do
> is reset the line counter when a VSYNC is written to.

Mmm... I dunno. Here is a description of combat´s VSYNC and VLBANK behaviour
on my emu. I reset the scanline counter to 0 when VSYNC ends, by
the way.

VBLANK ends on line 36, pixel 18.
VBLANK starts on line 257, pixel 9.
VSYNC starts on line 260, pixel 9.
VSYNC ends on line 262, pixel 9.

> PS: May I send a screenshot of my combat screen that I get in my emu to
> anyone?  The screen is scanline-truncated at the bottom for some reason,
> even though when I run, say RiverRaid, the screen looks perfect :/  Anyone
> willing to help?  Does Combat do anything special which I should be aware

I will give it a look. Anyway, I think it would be better to send it to the
list in jpg format.



Archives (includes files) at
Unsub & more at

Current Thread