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Member Since 23 Nov 2008
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#4138934 Altirra Extended BASIC

Posted by flashjazzcat on Sun Oct 21, 2018 11:38 AM


It's not just about speed, but also how much space and registers a long call takes.


ATXBasic's bank mechanism works as follows...


Thanks for the explanation. I had to look up 'thunk' (since I'd never heard of the term before), but having done so, I realise I use thunks too. :)


I opted to keep the bank and destination address directly behind the JSR to the 'thunk' since I wanted to pass arguments in all three registers. It is pretty expensive, but by avoiding inter-bank calls in performance-critical situations, it works out well enough. Similar methods are used in the GOS ROM, U1MB/Incognito PBI BIOS (which use 4 x 2KB banks) and the XEX loader (which uses 2 x 8K banks). The advantage of the expensive method is that I don't need to care much whether the JSR macro results in bank traversal or not (the macro picks the appropriate method depending on whether or not the target is in the same bank), although obviously one tries to pre-optimise things by positioning code such that inter-bank jumps are kept to a minimum.

#4137880 800XL U20 IC shows most pins low

Posted by flashjazzcat on Sat Oct 20, 2018 2:46 AM

@FJC welcome to my world :)

Yeah: I'm old. You need your wits about you in these toubleshooting topics, since they can become quite competitive. ;)

#4137581 800XL U20 IC shows most pins low

Posted by flashjazzcat on Fri Oct 19, 2018 4:21 PM

If the CPU crashes you should still get a video signal (even if black, you should get csync) so it's possible the CD4050 is bad. Does the machine show signs of SIO activity if you connect a disk drive? If it does, you have a video problem and you can focus on GTIA and U20.

#4137409 Altirra Extended BASIC

Posted by flashjazzcat on Fri Oct 19, 2018 12:54 PM

I guess he's asking if BASIC programs can be run without the ROM-based interpreter, to which I suppose the answer is no until such time as there's a compiler available.

#4137090 Altirra Extended BASIC

Posted by flashjazzcat on Fri Oct 19, 2018 4:52 AM

How critical is an address-based banking mechanism to inter-bank JSR performance? With regard to running the interpreter on carts with different banking schemes, part of the reason it's difficult to - say - replace the loader on the SIDE cart's external cart ROM space with Action! or MAC/65 is that said application would have to be recompiled for the target hardware. But that's not an issue for something which can be compiled for different banking schemes with the aid of a few macros and conditional assembly. It just strikes me that a build for SIDE's external cart would work very nicely for users running the SIDE cart stand-alone and running the HDD via the SDX SIDE.SYS driver. The interpreter would be launched via the SDX 'CAR' command.


As I say: I have no idea how cycle-critical the inter-bank jump mechanism is. I only know that it's probably more efficient than what I came up with for the GOS, which targets half a dozen different banking schemes. Instead of loading up A,X and Y with bank number and target address, I ended up placing the bank number and target address in-line with a JSR to the long JSR function. Most of the registers are preserved and while it's good enough, it's fairly expensive.

#4136593 Introducing: AntiX, the ANTIC Switch !

Posted by flashjazzcat on Thu Oct 18, 2018 12:15 PM

VBXE emulates GTIA on-board (although the emulated GTIA output appears only on the RGB signal), but relies on an actual ANTIC chip, so you'd need to shoe-horn two ANTICs onto the adapter, and I doubt that crossed anyone's mind during the VBXE design phase. Current revision Lotharek boards do have both NTSC and PAL master crystals, however, selectable by a jumper, so if you do a chip swap, you can actually get the proper frequency for legacy video without soldering anything.

#4135541 ATARI 800 XE - ON/OFF switch

Posted by flashjazzcat on Wed Oct 17, 2018 9:06 AM

hmmm peterson 320K for next to nothing or 100 dollars for a u1m... yeah...  320K easy to repair... u1m fried your f*cked. when it was 68-69 dollars it was fine... because of all it offered. Now not so much. If you have money to burn the U1M is the way to go, if not... have at it with a soldering iron...

Current price of 239PLN = 64USD according to XE Currency Converter.

#4134715 Ultimate 1MB, Incognito, 1088XEL and SIDE/SIDE2 Firmware Update Released

Posted by flashjazzcat on Tue Oct 16, 2018 9:24 AM

Yep: the ST mice are awful to use, although they do look good with an XE system. That's why I recommend third-party ST/Amiga mice, many of which are quite pleasant in use, and all of which plug straight into the joystick port without any additional fuss. There is (or was) even a build of the GOS which works directly with Amiga mice (no need for a switchable ST/Amiga device). Obviously when things progress somewhat, you'd just install the relevant mouse driver (Amiga or ST).

#4134128 Ultimate 1MB, Incognito, 1088XEL and SIDE/SIDE2 Firmware Update Released

Posted by flashjazzcat on Mon Oct 15, 2018 1:23 PM

My goto GOS controller is a 'Tecno Mouse' branded ST/Amiga (switchable) unit, but virtually any aftermarket ST or Amiga mouse is going to feel much nicer than those supplied the with machines. ST trackballs also work.


Mytek's TK-II adapter facilitates the use of PS/2 mice with the GOS if want to go down that route.

#4132655 The Missing Manual

Posted by flashjazzcat on Sat Oct 13, 2018 10:00 AM

Absolutely: I quite understand. I got very little sleep last night (as evidenced by this morning's video), and after posting in this thread, a second scan through the manual revealed that I'd probably misunderstood the meaning behind the title.

I have further revisions to make to the firmware manual (as well as an 'un-bricking' guide to add to the arsenal of documentation), and in an ideal world there'd be no gaps at all, but in reality the whole business is enormously time-consuming. That's the real answer for anyone who complains about documentation for this or that device being 'less than perfect': the creation of comprehensive documentation can be as laborious as the development of the software or hardware being documented, and is similarly subject to frequent revisions, corrections, and version control. I have no doubt at all that because of this I can be touchy about complaints regarding inadequate docs, but at the same time I fully appreciate that the exhaustive, in-depth documentation isn't what's required in every situation.


Anyway: I'm up to date with the link; what foxed me this morning is the fact that the call-outs are not text-searchable. ;) I will try to invest some time in careful reading of the latest revision next week. :)

#4132486 New version of ATARI 8 bit emulator released!

Posted by flashjazzcat on Sat Oct 13, 2018 3:23 AM

They will spy on you whatever. They might even see you as more of a need to spy on wierdo for not having Win10.

I think it's generally accepted that the deprecated operating systems are low-priority when it comes to telemetry data, etc. And it's a little easier to manually weed out and disable the 'phone home' stuff in XP, by all accounts.

#4132472 The Missing Manual

Posted by flashjazzcat on Sat Oct 13, 2018 1:45 AM

Don't forget to enable Stereo Pokey when emulating the 1088XEL in Altirra.
Urgh... forget what I said about the 'missing manual' part of the title. I can appreciate that having 'U1MB firmware' in the title does not imply that there was no manual for the 1088XEL U1MB firmware. I was reading it wrong: sorry. ;)

#4132470 Altirra 3.10 released

Posted by flashjazzcat on Sat Oct 13, 2018 1:27 AM

Can anyone answer my question about Device Done 144?

I only wish I could reproduce the error here.

#4132469 FujiConvert 0.1

Posted by flashjazzcat on Sat Oct 13, 2018 1:25 AM

Is Atarimax output only for the Atarimax 1Mb & 8Mb carts?

No idea about the cart types: pass.

Or, alternatively, does the IDE output media work with MyIDE 2 on the HDD side of things? Maybe since I use FJC's SpartaDOS driver for MyIDE 2 I can use the IDE file versions that way? or is this for only SiDE 2 and IDE 2.0?

The IDE files are intended to be used with my PDM Player, which doesn't use drivers of any kind since it must communicate directly with the hardware registers for reasons of speed. The downside to this is that you need a different version of the player for each IDE host adapter. I already released versions for U1MB/SIDE and XEL-CF (1088XEL), but haven't gotten around to making any others yet. Theoretically, the player could work with pretty much any IDE or even SCSI HDD available, given sufficient motivation to actually produce the builds.

I've got ONE THE!CART, ONE Atarima 8Mb (doesn't seem like a lot of room for much here) and I have MyIDE 2 with plenty of room on an 8GB CF card. I really don't want to use my only THE!CART to flash just one song file too, and have to reflash for every file, which is apparently the only way. I just got done flashing it for a bunch of software and would rather not go through that again. So, am I just SOL unless I want to reflash my THE!CART for every song file made for it? The best option is MyIDE 2 for me, but from what I can gather, this still isn't supported? Only SIDE or IDE + 2.0?

There's no player for IDE Plus or MYIDE yet, so unless you have U1MB/SIDE (or a 1088XEL), you'll need to flash THE!CART.

#4132036 Altirra 3.10 released

Posted by flashjazzcat on Fri Oct 12, 2018 11:12 AM

Avery, any chance of a program to hunt out idiots who seem to have added you to a spam list "for a laugh" so I can go around and fit my size 11 steel toe capped old work boots up their annoying ar**... (Pretty sure its not a bot 'harvest')

Sometimes you get lucky and they sign you up to something from their server machine and the IP is in the confirmation email. Forward to forum admin... sweet when that happens. ;)

The time machine functionality calls to mind reversible computing, so hopefully we can expect a version of Altirra which uses virtually no electricity whatsoever. :)