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phaeron

Altirra 2.80 released

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Hi all I'm trying to configure Altirra 2.80 to emulate U1MB and SIDE2, I've already added the firmware images for both U1MB and SIDE2 in the emulator, what am i supposed to do next? Thanks in advance!

Next would be to add Memory Config

 

post-10165-0-89299200-1474925190_thumb.png

 

Device

 

Side 2 -hard drive

Edited by rdea6
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I'd say the program deserves to crash, but that's just me. :) Mapping the Atari simply says 0 means NTSC, and the hardware flag at $D014 is supposed to be $0E for PAL.

Fair enough! Since the program I have that was crashing in AltirraOS was my own I have already changed it to detect PAL based $0E at $D014. Thanks! :)

 

Still good to be aware of that difference in behavior at $0062 in case it might be the cause of some other compatibility issues.

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Fair enough! Since the program I have that was crashing in AltirraOS was my own I have already changed it to detect PAL based $0E at $D014. Thanks! :)

 

Still good to be aware of that difference in behavior at $0062 in case it might be the cause of some other compatibility issues.

 

By the way, just correcting this because register $D014 is set to $0E if it is NTSC.

(So we were stating it backwards)

 

Per mapping the Atari:

53268 $D014
® Used to determine if the Atari is PAL (European and Israeli TV compatible when BITs I - 3 equal zero) or NTSC (North American compatible when BITs 1 - 3 equal one; 14 decimal, $E).
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Good spot. :) I ignore them both anyway and check max VCOUNT.

 

Unless it is written somewhere that the ZP location must read 1 if PAL, I'd say it's a bad idea to expect any specific non-zero value. Just react - in the case of $62 - to !=0 meaning PAL.

Edited by flashjazzcat
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Retry Drives C-O get this screen

attachicon.gifPRESS C-O BIOS15.PNG

 

Start+Reset to reset SDX on and press Cntr+B for a reboot of hard drive.

 

Uh, are you seeing this only when using Altirra's virtual SpartaDOS disk support? The volume label and file contents suggests this, and that means the comparison against real hardware is invalid.

 

It looks like the IDE+2 disk loader uses a unique way of identifying SDFS disks that doesn't match the way that SpartaDOS itself does disk detection, by checking the JMP instructions in the boot header. I'll have to see if I can tweak the boot sector to match this.

 

By the way, just correcting this because register $D014 is set to $0E if it is NTSC.

(So we were stating it backwards)

 

Per mapping the Atari:

53268 $D014

® Used to determine if the Atari is PAL (European and Israeli TV compatible when BITs I - 3 equal zero) or NTSC (North American compatible when BITs 1 - 3 equal one; 14 decimal, $E).

 

Sadly, while Mapping the Atari is an excellent reference, it has a bad habit of misleading people into using OS variables and hardware registers incorrectly. This particular entry is a repeat offender. Often people see $E and latch onto that, but the text subtly says bits 1-3. This is a nod to the official Atari documentation saying that only bits 1-3 should be checked, but what MTA fails to mention here is that bit 0 is always set regardless and the value you will actual read on NTSC is $0F. (The PAL register doesn't actually exist on an NTSC GTIA; the $0F just comes from the internal 4-bit read data bus being undriven and pulled up, just like any other unassigned GTIA read address.)

 

PALNTS ($62) is another case. The presence of this variable is documented in the XL Addendum; however, the actual values are not. Mapping the Atari often documents behaviors that are undocumented OS details, and so you can get into trouble by relying on what it says. The Atari Home Computer Operating System User's Manual is a much better reference for what is actually guaranteed in the OS variables; unfortunately, Atari did not document the 1200XL OS changes as rigorously, and AFAIK never documented the 800XL OS changes at all. I'll fix AltirraOS's setting of this variable, though, since it's trivial to do so.

 

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Hi Avery,

 

I also use the "ATARI XL ADDENDUM" frequently.

This has the changes from 400/800 to (12000) XL.

It reflects also the main changes to 800 XL.

What is not documented here are the PBI-details...

 

Having a compatible OS is a pita, you are right about people (ab)using OS variables and OS entry points.

I guess about now 20% of MyBIOS are patches to coop with these issues.

Beside that I try not to re-use global OS variables, better set them to a known value even not used in the alternative OS.

 

Anyhow, for anybody who want to try an alternative OS that also supports MyIDE-][, HSIO, BT and 400/800:

www.mr-atari.com/MyBIOS for the latest work in progress

 

Cheers,

Sijmen.

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Phaeron,

 

Any chance you could add the presets for Paddle controllers (CX-30) in the input section of Altirra? Currently, you have to manually setup the paddles using the "Stelladaptor II" (see attached).

 

post-27335-0-31116600-1475002931_thumb.jpg

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Hi,

I noticed a small bug in floating point functions in Altirra BASIC 1.51 (based on this article):

?LOG(1)
4.60517018E-10

?SQR(2^2)
1.99999999

?2^3
7.99999991

And this the expected result (how it works in Atari BASIC rev. C):

?LOG(1)
0

?SQR(2^2)
2

READY
?2^3
8

Regards Mira

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These are classic floating point accuracy issues. As has seen noted previously on this board, the fixes implemented by Atari BASIC rev. C aren't very good -- they work by looking for specific values and truncating the result. For instance, the routine for LOG(x) looks for a result between 1*10^-8 and 8*10^8 and forces it to zero. I'm not too fond of replicating hacks like that just to make the results look pretty.

 

Atari Calculator uses a different method, which is to show slightly fewer digits than are calculated and use the guard digits to round the result. While a better method, this can't be used by BASIC because it would prevent numbers from round-tripping properly when converted to text and back.

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Hi Avery, just a tiny itty bitty feature request, in the cheater could you add the ability to label the cheat made, ie Infinite Time etc. Its just that if you do a load of selectable cheats no one else can tell what each one does unless I make a little file to go with it, a label would sort that...

 

Any way, please give it a thought, thank you whatever the answer.

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Avery - first of all - thank you very much for this wonderful emulator - Altirra is truly amazing and is near perfect !!!!

 

There is only one minor gripe that prevents me from using any versions newer than 2.6 test 12 - scanline emulation. Scanlines were perfectly emulated up until Altirra 2.6 as sharp visible lines, but in later versions they became blurry and generic and look nothing like the real CRT (when compared to picture on my Sony WEGA 27")

 

Please see the attached screenshot for comparison. Just curious - would it be possible to bring back the old scanlines or have an option to switch ?

 

Once again , thank you very much for all your hard work !

post-29247-0-68323700-1476145014_thumb.png

Edited by subjugator
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I've tried Altirra 2.80, recently, but I've noticed a flaw in the audio that wasn't there at all in 2.70, namely random clicking every now and then. What could be the cause of that?

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Do you have an Nvidia gfx card?

 

I find that it installs some HD Audio driver for some reason even though my creative card has its own drivers.

 

I started noticing little clicks but not just in Altirra, just random ones.

 

Uninstalled the HD thing and it seems to have cured it..

 

Could be something entirely different though...

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Yes, I have a mid- to high-range card, the 960GTX.

 

I just checked, and it seems 2.80 doesn't work well with a lot of demos neither - on 2.70, Numen by Taquart performs much better than on 2.80, where at one point it will stutter badly, and it is unavoidable.

 

I am particularly peeved as I have just recorded a whole bunch of demos on 2.80, having forgotten the above issues, and now I'll have to re-record them all again on 2.70!

 

I don't have a Creative card, the motherboard audio works perfectly fine. I haven't had a sound card for well over a decade.

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The onboards are normally pretty decent compared to the budget main boards back in the day that had some awful cheap as chips sound card built in.

 

As for the demo's, don't play many of them but as they normally push the emulation its the most likely place to reveal any issues, hopefully it able to be replicated so Avery can sort out the problem.

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Do you have an Nvidia gfx card?

 

I find that it installs some HD Audio driver for some reason even though my creative card has its own drivers.

 

I started noticing little clicks but not just in Altirra, just random ones.

 

Uninstalled the HD thing and it seems to have cured it..

 

Could be something entirely different though...

 

It installs the HD driver so, if you have a BD-ROM in your machine and are connecting to your monitor via HDMI then you get compliant end-to-end HDCP copy protection - basically so you can play the audio from BD disks on you monitor without having to buy a more expensive card. Of course you can also use this audio device for your whole machine as well. Sometimes I have given this a try when debating doing away with my powered speakers, but in the end its all just more to go wrong in my opinion. I suppose some people might also be using the card in a media-centre so I would have more relevance there.

 

I agree though, I have always used Creative boards when I could afford them. In my experience the onboard sound provided by motherboards is always crap. At least it was - I have not used it since AC97 was still a thing nor upgraded my desktop in ten years. So I guess its really a case of what the hell do I know!

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Shudder, makes me think back to the Quemm and setting up the blaster variables in DOS, god I hated all that even though the software normally did it for you (sadly some installers didn't even work unless the base mem was right. Thankfully Windows came along and started to do more for you to the point now that it recognises pretty much everything for you......ish....

 

Oh, re the sound, I just remembered that I remember a few times when the SIO noise of booting with no disk drive (the farty type noise before it goes to either BASIC or Self test) sounded wrong, it was as if it was a tune but one or more of the voices was turned off and it felt less bassy. Obviously its not a tune but it is just the easiest way to describe it. reset the settings and it came back but I'm sure I've heard the same thing since. If I turn my real Atari on the sound is deep and raspy but what I was hearing at times on the emulator was more mid range than anything.

 

Most likely emulation being reset during operation and perhaps settings not 100% being refreshed like a cold start. (as if I have a clue :) )

 

I only mention it because Fobane's clicking issue as it might be related...Like his clicking it was random...

Edited by Mclaneinc

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I figured on-board sound these days was simply a case of using a simple DAC, as Windows handles everything to do with audio and just sends it out through the DAC.

 

However, a long time ago I discovered that when I plugged in speakers through the audio out socket on the motherboard, I could hear interference from the graphics card, as the output was converted to analogue and that's when the interference started. Then I got a USB device that was a simple DAC and moved it as far away from the PC as I could, which reduced the interference. Lastly, I simply set the graphics card to output audio via HDMI and the interference has stopped outright, as the audio is digital all the way to the monitor which THEN converts it to analogue for output via it's own audio socket.

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Tech talk, it almost sounds dirty :)

 

This is just about at my level, when Avery starts with the heavy duty tech speak I just get this totally lost look on my face and feel like the kid who got the D for Dunce cap in school (a looong time ago when that happened in schools, the kids would knife you if you tried it these days)

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Back in late-2002 ASUS came out with what were in my opinion the best family of motherboards for WinXP and the then-excellent Athlon XP processors - the A7N8xxx models. The so called 'deluxe' version came with an onboard hardware processor to convert the standard AC97 sound in to Dolby Digital and a TOSLink back plane that allowed you to output all audio from the PC as optical AC3 to a compliant A/V Amplifier. That was a really big deal back then and worked... pretty well, especially the handful of games whose native AC3 audio (often PC ports of XBox games) could be passed straight-through to the amplifier. However it was not brilliant for native desktop sound and my system at least suffered a lot of interference from the power unit. In the end I bought the Dolby Digital version of the SBLive! 5.1 and used that for five years or more.

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People often forget the level of RF a power set up generates let alone what the chipset itself can generate which leads me nicely back on topic to Averys addition of the SIO interference noise which I'd not turned on and yet again its another wonderful little touch that sells the emulation as being closer to the real thing. Was playing a game that did a big silent load and sat there thinking "I'm sure I remembered the SIO making a faint noise" back then. I then remembered the changes list and there it was in audio, serial noise..

 

Such a small idea but it just makes it feel even better for the taint sio load...

 

Thank you Avery...

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i forgot..

how i can save Altirra ROM to PC via? thanks

Edited by w1k

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Do you mean the internal Altirra version of the OS?

 

If yes then I believe its available in the source code file in the OUT directory but its not bootable by Altirra as its used internally only...

 

As for dumping it yourself I'd imagine its the same way you would dump any OS rom and just save the particular area of memory to disk but again I doubt it would be useable?

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