Marius Posted May 28, 2014 Share Posted May 28, 2014 Is there a way to check whether you have OS B or OS A? The title screen gives strange image. Just like a characterset is not working right. Quote Link to comment Share on other sites More sharing options...
Marius Posted May 28, 2014 Share Posted May 28, 2014 (edited) It is an OS A thing. With my emulator with OS A I have the same thing (tested this time with rolltris, but thetris gives same issue) You can find OS A here Edited May 28, 2014 by ProWizard Quote Link to comment Share on other sites More sharing options...
MaPa Posted May 28, 2014 Author Share Posted May 28, 2014 Looks like there is no DLI happening. Strange that ingame it works Quote Link to comment Share on other sites More sharing options...
Marius Posted May 28, 2014 Share Posted May 28, 2014 (edited) Yes… I thought my ANTIC was defect. So I took the whole thing apart (AGAIN!) and started swapping components for about 2 hours, until I finally realized that my Atari 800 indeed has OS roms dated 1981, while my Atari 400 has rom chips dated 1980. Then I start looking on internet for OS A … and found that link. Then I saw on my screen the same as I see with my Atari 400. Although I want my Atari 400 to be as compatible as possible, I leave it with OS A… that is absolutely a rarity here in my house. Yes in game is perfect. I have played a lot of thetris today on the 400. That was pretty cool. (Yes besides the taking apart and re-assembling the atari 400 a few times) Edited May 28, 2014 by ProWizard Quote Link to comment Share on other sites More sharing options...
Xuel Posted May 28, 2014 Share Posted May 28, 2014 OS A's SETVBV routine resets NMIEN to $40 whereas the OS B's SETVBV routine doesn't touch NMIEN. So you just need to reset NMIEN to $C0 after calling SETVBV to make it work on OS A. 1 Quote Link to comment Share on other sites More sharing options...
Marius Posted May 28, 2014 Share Posted May 28, 2014 @Xuel; do you have a link to interesting information about these differences? I just found out that my 400 has this OS A, and I would love to explore it's (im)possibilities. Thanks a lot anyway! Quote Link to comment Share on other sites More sharing options...
Xuel Posted May 28, 2014 Share Posted May 28, 2014 I'm afraid I don't have any links but I agree that would be interesting! Given MaPa's statement that DLIs must not be firing, I deduced that SETVBV was the culprit simply by trying OS A and OS B and setting a breakpoint on writes to NMIEN in Altirra (bx "write=NMIEN"). When the breakpoint hits, you can see in the CPU history that the call to SETVBV is the event leading up to NMIEN getting clobbered with $40. Quote Link to comment Share on other sites More sharing options...
Xuel Posted May 28, 2014 Share Posted May 28, 2014 Since MaPa helpfully published the code, I was able to easily patch it with a one-line fix: thetris-osa-fix.xex --- thetris.xsm~ 2014-05-28 15:37:08.284105500 -0500 +++ thetris.xsm 2014-05-28 15:37:40.597953700 -0500 @@ -2628,7 +2628,7 @@ ldx >vbi lda #7 jsr $e45c + mva #$c0 $d40e lda #1 1 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted May 28, 2014 Share Posted May 28, 2014 Yes… I thought my ANTIC was defect. So I took the whole thing apart (AGAIN!) and started swapping components for about 2 hours, until I finally realized that my Atari 800 indeed has OS roms dated 1981, while my Atari 400 has rom chips dated 1980. Then I start looking on internet for OS A … and found that link. Then I saw on my screen the same as I see with my Atari 400. Although I want my Atari 400 to be as compatible as possible, I leave it with OS A… that is absolutely a rarity here in my house. Yes in game is perfect. I have played a lot of thetris today on the 400. That was pretty cool. (Yes besides the taking apart and re-assembling the atari 400 a few times) Can you please test and see if your PAL Rev A 400 has CTIA or GTIA? In BASIC, just do a POKE 623,64. If the screen goes black you are GTIA, else you are CTIA. If CTIA, I am doubly jealous!!! Quote Link to comment Share on other sites More sharing options...
Marius Posted May 29, 2014 Share Posted May 29, 2014 Gtia. No need to be jealous ; Quote Link to comment Share on other sites More sharing options...
Marius Posted May 29, 2014 Share Posted May 29, 2014 Since MaPa helpfully published the code, I was able to easily patch it with a one-line fix: thetris-osa-fix.xex --- thetris.xsm~ 2014-05-28 15:37:08.284105500 -0500 +++ thetris.xsm 2014-05-28 15:37:40.597953700 -0500 @@ -2628,7 +2628,7 @@ ldx >vbi lda #7 jsr $e45c + mva #$c0 $d40e lda #1 Hi! Since I don't have those crossassemblers could you please do rolltris too for me? Thank you really a lot! It's much appreciated! Marius Quote Link to comment Share on other sites More sharing options...
Xuel Posted May 29, 2014 Share Posted May 29, 2014 Since I don't have those crossassemblers could you please do rolltris too for me? Here you go: rolltris-osa-fix.xex 1 Quote Link to comment Share on other sites More sharing options...
Marius Posted May 29, 2014 Share Posted May 29, 2014 @Xuel Thank you VERY much. I'm making this great AtariMax 8Mbit cart for my so cool Atari 400. It's getting really something. Quote Link to comment Share on other sites More sharing options...
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