|
|
Atari coding BBS
| Re: Another STE question |
|---|
|
Posted by: evil
|
May,12.2012-14:45
|
As previously said, the blitter uses up 64 bus cycles each turn - that's half a scanline. So you need to interrupt at least half a scanline earlier than usual.
You say the screen flickers, with this I assume you mean the lower border flickers? And then you say you havn't implemented the lower border code with earlier interrupt - of course it will be unstable then. 256 CPU cycles is a huge blow to the "normal" lower border rout. It will fail for certain if there are blitter operations going on around that scanline.
So basicly:
1. Interrupt one scanline early
2. Change the background colour so you can see where the interupt actually begins, this should give you an idea how unstable it is due to 256 CPU cycles blitter pass
3. If the interupt always happens on the line before the lower border removal, then you're safe, just wait for HBL as your code example. Yep you will lost about a scanline worth of precessing time, but you have to live with it
4. If it doesn't always happen on the same line, I think you need to read the screen address counter to determinate which line you are actually at before deciding to wait for HBL or do the border removal.
Yes, it's fiddly. But that's nature when you do stuff that the hardware isn't supposed to do (lower border removal :-)
--
Anders Eriksson
ae@dhs.nu
|
[All messages in this thread] [Start new thread]
|
Topic
|
Posted by
|
Date
|
|
Another STE question
|
Bod/STAX
|
May,10.2012-20:28
|
|
Re: Another STE question
|
RA/pdx
|
May,11.2012-11:56
|
|
Re: Another STE question
|
Bod/STAX
|
May,11.2012-13:06
|
|
Re: Another STE question
|
Cyprian
|
May,11.2012-13:17
|
|
Re: Another STE question
|
RA/pdx
|
May,11.2012-21:04
|
|
Re: Another STE question
|
Bod/STAX
|
May,12.2012-12:41
|
|
Re: Another STE question
|
evil
|
May,12.2012-14:45
|
|
Re: Another STE question
|
Bod/STAX
|
May,12.2012-17:56
|
|
Re: Another STE question
|
evil
|
May,12.2012-18:24
|
|
Re: Another STE question
|
Bod/STAX
|
May,12.2012-21:20
|
|
Re: Another STE question
|
evil
|
May,13.2012-13:17
|
|
Re: Another STE question
|
Frank b
|
May,14.2012-20:16
|
|
Re: Another STE question
|
Cyprian
|
May,13.2012-18:22
|
|
Re: Another STE question
|
Patrice Mandin
|
May,13.2012-14:38
|
|
Re: Another STE question
|
Bod/STAX
|
May,15.2012-11:15
|
|
Re: Another STE question
|
evil
|
May,16.2012-09:17
|
|
Re: Another STE question
|
Bod/STAX
|
May,16.2012-21:30
|
|
Re: Another STE question
|
evil
|
May,16.2012-22:40
|
|
Re: Another STE question
|
Bod/STAX
|
May,17.2012-01:10
|
|
Re: Another STE question
|
Klaz
|
May,17.2012-14:08
|
|
Re: Another STE question
|
Bod/STAX
|
May,17.2012-21:35
|
|
Re: Another STE question
|
dan/pdx
|
May,18.2012-16:03
|
|
Re: Another STE question
|
Bod/STAX
|
May,18.2012-20:24
|
|
Re: Another STE question
|
Bod/STAX
|
May,19.2012-16:21
|
What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
|
