+Nezgar Posted June 7, 2020 Share Posted June 7, 2020 Amongst many other things I acquired in a lot from an old friend was a set of 9 intel D2764A EPROM's. 7 of them contained the "01" dump, 2 containted the "02" dump. There is no readable text, and it does not appear to be 6502 ML. Viewing the bitmaps in Omnivore also shows no image type data or character sets. - PC BIOS or video card ROM's would have some readable text or text fonts... Part of the collection contains disks from a computer store he and friends were involved with, and there is also a mixture of osborne, Apple 2, and DOS disks as well, so who knows what platform the EPROMS were intended for, maybe some chance its "Atari Related". They were stuffed in a wallet-sized Control Data box, which may also be a misnomer. Interested if anyone can glean anything from these! 01 CRC32 90846B07.BIN 02 CRC32 443EEFA3.BIN Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted June 8, 2020 Share Posted June 8, 2020 (edited) Any arcade involvement with your old friend? 01 and 02 dumps tend to be from arcade boards a lot of the time? Edited June 8, 2020 by Mclaneinc Quote Link to comment Share on other sites More sharing options...
+Nezgar Posted June 8, 2020 Author Share Posted June 8, 2020 3 hours ago, Mclaneinc said: Any arcade involvement with your old friend? 01 and 02 dumps tend to be from arcade boards a lot of the time? No arcade connection that I know of. But got me thinking it might be audio data, so tried importing it as raw audio into Audacity but mostly sounds like random data there too. The filenames are no hint, I dumped this data from unlabelled EPROM's myself, so had to name them something. Labels covering the windows were removed, so it's possible that the data on them was from a 3rd party and the chips were intended to be erased and re-programmed. Anyhow.. it's interesting the first 255 bytes are the same between the two differing dumps: Quote Link to comment Share on other sites More sharing options...
1050 Posted June 8, 2020 Share Posted June 8, 2020 That was about I had to report to you as well, the identical first page in both files. I wouldn't call it non 6502 code since rarely some is about, but it's not typical of Atari 6502 I'm used to seeing at all. Very little of it would work and that just doesn't seem like memory space compromised op code then. Dunno what to think of it. Quote Link to comment Share on other sites More sharing options...
+DjayBee Posted June 8, 2020 Share Posted June 8, 2020 IMHO they are two versions of the same program because they share a lot (red bytes differ): Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted June 8, 2020 Share Posted June 8, 2020 are the differing data shifted/moved to allow for relocation in some way? or perhaps a complete swap? Quote Link to comment Share on other sites More sharing options...
+DjayBee Posted June 8, 2020 Share Posted June 8, 2020 I'd say that it is not relocated because the offsets into the file differ. Both sides start at $100. The left ends at file offset $383, the right one at $37D. Quote Link to comment Share on other sites More sharing options...
ClausB Posted June 8, 2020 Share Posted June 8, 2020 The bytes from addresses 06 through BB look like a LUT (look-up table) of some function which increases less as it grows, like a square root. I typed a cross-section of the table into a spreadsheet, squared the values, scaled down by 256, and took consecutive differences. It does indeed look like a square root approximation table! 3 Quote Link to comment Share on other sites More sharing options...
+warerat Posted June 9, 2020 Share Posted June 9, 2020 10 hours ago, Nezgar said: No arcade connection that I know of. But got me thinking it might be audio data, so tried importing it as raw audio into Audacity but mostly sounds like random data there too. The filenames are no hint, I dumped this data from unlabelled EPROM's myself, so had to name them something. Labels covering the windows were removed, so it's possible that the data on them was from a 3rd party and the chips were intended to be erased and re-programmed. Anyhow.. it's interesting the first 255 bytes are the same between the two differing dumps: Not 6502, but close. It is 6800 (or close derivative). I’m using the 01 file. Look at the last eight bytes. There’s four big-endian addresses. The reset vector goes to $F259, the NMI vector goes to $E4C1. In 6800-speak at $F259 you have: 1251 C1 AA cmpb #$AA 1253 27 03 beq $1258 1255 73 00 1C com $001C 1258 39 rts 1259 0F sei 125A 8E 00 7E lds #$007E 125D 86 66 ldaa #$66 125F B7 40 00 staa $4000 1262 CE 00 00 ldx #$0000 1265 86 AA ldaa #$AA 1267 A7 00 staa $00,x 1269 E6 00 ldab $00,x 126B 11 cba 126C 26 C3 bne $1231 126E 43 coma 126F 2A F6 bpl $1267 1271 6F 00 clr $00,x 1273 08 inx 1274 8C 00 80 cpx #$0080 1277 26 EC bne $1265 1279 86 20 ldaa #$20 127B 97 1F staa $1F 127D 86 31 ldaa #$31 127F 97 30 staa $30 1281 CE 01 A0 ldx #$01A0 1284 DF 5D stx $5D 1286 BD F2 23 jsr $F223 Looks like a valid sequence for memory test code to me, including disabling interrupts on power up. That's no coincidence. The NMI vector code at $E4C1: 04B8 86 02 ldaa #$02 04BA 8D 89 bsr $0445 04BC 8D D0 bsr $048E 04BE 8D A1 bsr $0461 04C0 39 rts 04C1 C6 57 ldab #$57 04C3 BD F1 F0 jsr $F1F0 04C6 3B rti Even terminates with an RTI, that's no coincidence either. 8 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted June 9, 2020 Share Posted June 9, 2020 Digital archeology - I love this stuff! Have loved it most of my life, it's so fun to be able to find stuff, reverse engineer it, etc. Doubly so to watch the group of people on this forum do it, since I cannot. 1 Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 9, 2020 Share Posted June 9, 2020 2nd photo in Hex screen. Why I am seen "G. 9" that means Graphics 9 mode ? Am I wrong at this time ? Quote Link to comment Share on other sites More sharing options...
lbaeza Posted June 9, 2020 Share Posted June 9, 2020 G. 9 means GOTO 9, not Graphics 9. That would be GR. 9. Kind regards, Luis. Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 9, 2020 Share Posted June 9, 2020 Hello Ibaeza, Yes... that would be correct ... thank you for the answer. I forget some of abbreviations on Atari BASIC keywords ..... (shh ....). So it is BASIC source code in hex or what ? Yes, it is mystery but is BASIC or something else ? Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted June 9, 2020 Share Posted June 9, 2020 6 hours ago, Caterpiggle said: Yes, it is mystery but is BASIC or something else ? I vote “coincidence.” The post above by @warerat makes a convincing case for it being some type 6800 code. Sometimes those shapes in the clouds are really just clouds. 1 Quote Link to comment Share on other sites More sharing options...
ClausB Posted June 9, 2020 Share Posted June 9, 2020 Yes, especially since the period is not an ASCII period, it's hex 11. Also there's no other BASIC code visible. 6800 derivatives were used widely in automotive controllers. Or it could be some industrial controller. 1 Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted June 9, 2020 Share Posted June 9, 2020 (edited) Loving the sleuthing going on here...I'd vote that the weird basic codes are just random as others have said but the 6800 code is structured and sensible so its good sign, sadly we will probably never know what is really is for.. Shame, we all like an end to a mystery...Well a lot of people do, some prefer the element of mystery to persist. Edited June 9, 2020 by Mclaneinc Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted June 9, 2020 Share Posted June 9, 2020 hmmm memory test or Tuning chips for a car maybe... yeah that might just be the ticket... Quote Link to comment Share on other sites More sharing options...
+Stephen Posted June 9, 2020 Share Posted June 9, 2020 Here's a 16kB BIN from a 1987 Daytona turbo. That vehicle used a 6803CPU, I believe in 1988 the engine control computer upgraded to a faster 6809. 87_22_t1_864.BIN 2 Quote Link to comment Share on other sites More sharing options...
Gavin1968 Posted June 12, 2020 Share Posted June 12, 2020 On 6/7/2020 at 2:57 PM, Nezgar said: Interested if anyone can glean anything from these! Did you try uploading them to ROM Ident? http://romident.coinopflorida.com/ Quote Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.