XEX starting at $700

[Mr.Holub]

Dear all,

 

I have several XEX files that starts at $700 which causes issues with loading on real hardware, as most of loaders don't fit below $700.

Would be possible to create boot disk with loader below $700?

Does exist any other solution?

[vitoco]

I'm not sure, but I think that I have seen a loader that worked in lower memory (somewhere between page 4 and 6).

 

Probably some packers (compressors) could load compressed data to somewhere in the upper memory and then unpack the data into the real location.

 

BTW, which kind of programs are those?

 

[+CharlieChaplin]

And errrm, what's the size of these programs ? If they are <= 32kbytes and do not use INIT (just a RUN adress), then Super-Copy can "relocate" them to a DOS-friendly memory adress of $1F00-xxxx and RUN adress 1F3F...

 

http://www.atarimania.com/utility-atari-400-800-xl-xe-super-copy_15934.html

 

 

[+MrFish]

Quote

XEX starting at $700

 

LOL... I'd never give $700 for an XEX. Most XEX's are worth way less than that; and in fact many of the best ones are totally free. A few may be worth as much as $100 (very few); but that's only for CIB copies with all the packaging bells and whistles. Ebay's prices are just getting WAY too out of hand these days. People need to stop overpaying for what is obviously just a bunch of hype and herd-mentality retro-shopping mania. Don't give in to all these ethicless, opportunist ripoff artists.
 

Edited February 26, 2021 by MrFish

[_The Doctor__]

oh the load address money puns are rounding the corners!

[Rybags]

Plenty of loaders will work with Xex at $700.  $600 or $700 was a fairly common load address for plenty of tapes and single stage disks.

 

This is an ED disk image with a 5 sector boot menu that I wrote based on an existing on in the 80s - I made it to handle low memory boots by performing the load portion from code relocated to low memory (it uses part of the IOCB area) - not sure what the lowest load address supported is but probably something around $520.

 

 

Games Disk 16b.ATR

Edited February 26, 2021 by Rybags

[_The Doctor__]

also how low does LiteDOS go...

http://www.mr-atari.com/Mr.Atari/LiteDOS/

 

I forget but I am certain it's tiny

 

also what of xBIOS?

 

how does APE's loader go as well?

Edited February 26, 2021 by _The Doctor__

[+Stephen]

I believe APE loader can go as low as $400.

[+CharlieChaplin]

27 minutes ago, _The Doctor__ said:

also how low does LiteDOS go...

http://www.mr-atari.com/Mr.Atari/LiteDOS/

 

I forget but I am certain it's tiny

 

also what of xBIOS?

 

how does APE's loader go as well?

 

LiteDOS memlo: $1000 = too high!

 

Ape loader: Afaik, requires a PC or is there a version for 5,25" A8 floppy disks?

 

Wasn't XBIOS memlo $0800 and one would have to change it for a lower memlo?

 

[_The Doctor__]

litedos xs?

litedos ro?

dunno, about apeloader as a standalone but why not? and lots of 3 sector loaders out there... wasn't this already covered

during some talk of loading disk stuff with a 400 etc...

food for search and thought in any case

@mr-atari

what's the memlo of xs and ro?

Edited February 26, 2021 by _The Doctor__

[Wrathchild]

4 hours ago, Mr.Holub said:

causes issues with loading on real hardware

How are you actually loading them as that's critical to where any binary loader bootstrap is being loaded, for example Ultimate Cart, AVG Cart, SIO2SD etc?

 

As @vitoco mentioned, one of the easiest ways to get around it is to pump it through a packer to load at a higher address, e.g.

exomizer sfx bin -n -t 168 -Di_table_addr=$500 -Di_load_addr=$5000 -o new.xex old.xex

 

Edited February 26, 2021 by Wrathchild

[Rybags]

Isn't there an APE/SIO2PC loader around that lives in the stack?

 

Where the loader boots to isn't really important - the portion that performs the actual loading can be moved and ran from the stack and parts of spare low memory.

Of course you also need that 128 bytes for the buffer but generally no games will load there, plenty of software might use it as workspace but that's after loading is complete.

[xxl]

10 hours ago, Mr.Holub said:

I have several XEX files that starts at $700 which causes issues with loading on real hardware

if possible, put one example

[mr-atari]

6 hours ago, _The Doctor__ said:

litedos xs?

litedos ro?

dunno, about apeloader as a standalone but why not? and lots of 3 sector loaders out there... wasn't this already covered

during some talk of loading disk stuff with a 400 etc...

food for search and thought in any case

@mr-atari

what's the memlo of xs and ro?

But they are still handler based, so it installs D to the device-table.

-XS $BD0

-RO $9FF
Doing a destructive load, you can start at loading $8F4

In theory, a loader, can be much smaller....

 

[xxl]

I don't think it's a good idea to install the "D" driver for the loader and place it that low but it's possible. in a DOS attachment that leaves memory free from $ 700, fits in the boot sector, configures itself to sector size 128/256. automatically runs the "AUTORUN" file

dos700.atr

 

---

a much better solution is to add a configuration file to xBIOS and then it will allow you to load in a civilized way even from $200 (with OS OFF)

 

---

or if you reeeeeallly need OS and "D" then xBootDOS memlo $980, all formats dos2, dir size 64/128, binary load for Atari Basic etc.

 

 

https://xxl.atari.pl/xbootdos/

 

Edited February 26, 2021 by xxl

[StickJock]

A friend of mine in high school wrote a bootable loader that ran out of the stack.  There were very few games that it couldn't load - it's been over three decades, but as far as I can remember, it only choked on one or two titles.  He called it the Batillac, after Batfink's car.  It only worked on Atari DOS formatted disks, not SpartaDOS, but it had the capability to read a new directory by hitting space (so you could launch games from another disk) as well as writing itself onto another floppy.  IIRC, I think it took something like 7 sectors.

[Gunstar]

15 hours ago, _The Doctor__ said:

oh the load address money puns are rounding the corners!

I can see why; when I first clicked on this topic I was thinking "what is this about then" with my mind going straight to money from the thread title. But for me it's because I'm not used to seeing $700 as a I use MyIDE II Fat32 a lot and I usually have it set at $600. I didn't even remember that $700 was a starting address for loaders. If the title was 'XEX starting at $600' I'd have caught on to the subject matter instantly.

[+Nezgar]

Maybe it would work if the file is placed on a SpartaDOS disk and then set with the "BOOT" command?

 

From the SDCS documentation:

The DOS loader on the first three sectors of each SpartaDOS 2.x
formatted diskette, can load and run files in the same manner as a
command file. Normally DOS is loaded, but actually anything could be
loaded as long as it avoids the loader memory ($2E00-$3180).
<snip>

Example
	BOOT STAR.BIN
When this diskette is booted, it will immediately try to load and run the file
STAR.BIN.

I've made "quick boot" disks for some utilities this way as long as they're single-segment loaders.. Some games, RAM testers, UAV colour/artifact test utility etc worked...

[xxl]

1 hour ago, Nezgar said:

as long as it avoids the loader memory ($2E00-$3180).

it's a joke. right? unless a misprint.

[+Nezgar]

1 hour ago, xxl said:

it's a joke. right? unless a misprint.

I guess it would make sense for a DOS loader, if it loads below that, and then is free for re-use once control is transferred...

[flashjazzcat]

Exactly. No useful FMS will occupy that memory area.

[Mr.Holub]

On 2/26/2021 at 1:06 AM, Rybags said:

Plenty of loaders will work with Xex at $700.  $600 or $700 was a fairly common load address for plenty of tapes and single stage disks.

 

This is an ED disk image with a 5 sector boot menu that I wrote based on an existing on in the 80s - I made it to handle low memory boots by performing the load portion from code relocated to low memory (it uses part of the IOCB area) - not sure what the lowest load address supported is but probably something around $520.

 

 

Games Disk 16b.ATR 130.02 kB · 7 downloads

Thank you for example, however how can I use this to use my own XEX file? Does exist any tool for this or do I have to use an hexa editor? Sorry for lame questions but I haven't done any programming on Atari 8bit.

[Mr.Holub]

18 hours ago, Gunstar said:

I can see why; when I first clicked on this topic I was thinking "what is this about then" with my mind going straight to money from the thread title. But for me it's because I'm not used to seeing $700 as a I use MyIDE II Fat32 a lot and I usually have it set at $600. I didn't even remember that $700 was a starting address for loaders. If the title was 'XEX starting at $600' I'd have caught on to the subject matter instantly.

Well these are binaries converted from tapes using loader "TURBO" which was frequently used in Europe in 80's and 90's. I has allowed higher loading speeds with modified tape drives.

Loading address was low on these, and when converted in XEX, it causes problems with most of loaders on real hardware.

[Rybags]

Hex editor?  Why?

 

Just delete the files from the disk and put your own on there.

Back in the day I used to have to create the initial disk manually though... copied the first 5 sectors then manually adjusted the VTOC bitmap to mark 4-5 in use.

[Mr.Holub]

On 2/26/2021 at 2:47 AM, Wrathchild said:

How are you actually loading them as that's critical to where any binary loader bootstrap is being loaded, for example Ultimate Cart, AVG Cart, SIO2SD etc?

 

As @vitoco mentioned, one of the easiest ways to get around it is to pump it through a packer to load at a higher address, e.g.

exomizer sfx bin -n -t 168 -Di_table_addr=$500 -Di_load_addr=$5000 -o new.xex old.xex

 

I favor AVG Cart at the moment. I also own Sdrive, which can its loader put as low as $500 however most of loaders exceeds $700 so I'm looking for a way how to solve this. Thank you for an example with exomizer. I will try this and let you know what happened.