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Omnimaga => News => Topic started by: Juju on October 13, 2011, 06:39:49 pm

Title: Randy Compton releases the first TI-80 emulator
Post by: Juju on October 13, 2011, 06:39:49 pm: The TI-80 calculator came out in 1995 and was, with the TI-84 Pocket.fr, the smallest of the TI calculators ever released. Not much was known of it, with its proprietary processor, its tiny 64*48 screen and its lack of a link port (unless you have the ViewScreen model, who have a port for linking with a computer to take screenshots).

As he told us on TI-Planet (http://tiplanet.org/forum/viewtopic.php?t=8323), in February/March 2010, critor managed to dump both the 3.0 and 4.0 versions of the ROM with a EEPROM programmer and began analysing them. The mysteries of the TI-80 could be solved, but no. None of the 32KB of code could be recognized, since it's a proprietary processor and not a z80 like the TI-73 to 86, and a lot of the system messages seemed to be lacking from the ROM, as if part of the ROM was stored somewhere else. But where is the missing part of ROM? The TI-80 actually stocked the ROM in two different chips: a LH5359 ROM of 64KB capacity, and the proprietary Toshiba T6M53A processor. Unfortunately, no documentation on this processor had been found and no other known devices uses it.

Fortunately, Randy Compton studied the ROMs Critor dumped and found out a TI-BASIC glitch allowing him to dump the entire ROM on-screen. From there, he found 16KB was missing for a total of 48KB and began transcribing the ROM character by character. 97% of the ROM was dumped this way, the rest was non-displayable characters and pairs of codes showing the same character.

Randy didn't stopped there. He then managed to get his hands on a rare TI-80 ViewScreen with ROM 4.0, who have a linkport, and wrote the first ever assembly program, allowing him to dump the entire ROM through the link port, only used until then to take screenshots. The first complete ROM dumping of a TI-80 v4.0 was made.

To conclude this act of wizardry, Randy then wrote the first ever TI-80 emulator, made available today on TICalc (http://www.ticalc.org/archives/files/fileinfo/442/44237.html) and TI-Planet (http://tiplanet.org/forum/archives_voir.php?id=3735) (in french). He also made a documentation available here (http://www.ticalc.org/archives/files/fileinfo/442/44236.html). The TI-80, the last pre-Nspire calculator to lack an emulator, is now emulated. Randy won't stop there either. He also announced a kernel allowing ASM programs to be ran, a dumping program (the ROM isn't included with the emulator) and programs to transfer data via the link port.

After 15 years, the last locked TI calculator has now been unlocked, thanks to Randy Compton.
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: calcdude84se on October 13, 2011, 06:53:09 pm: I saw this on ticalc.org this morning at school, and would have posted about it if Omnimaga weren't blocked there. :/
However, it's not very useful for most of us, who don't have a ROM :P
A great achievement nonetheless! :D
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: parserp on October 13, 2011, 06:57:32 pm: Quote from: calcdude84se on October 13, 2011, 06:53:09 pm
I saw this on ticalc.org this morning at school, and would have posted about it if Omnimaga weren't blocked there. :/
However, it's not very useful for most of us, who don't have a ROM :P
A great achievement nonetheless! :D
Omni's blocked at your school?
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: willrandship on October 13, 2011, 07:23:59 pm: Mine too.

And wow, that's quite an adventure! Is the TI-80 viewscreen (the actual screen, not the calc) just like the 82-84+ viewscreen or is it different?
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: Deep Toaster on October 13, 2011, 07:27:32 pm: Whoakay, awesome O.O

Even the TI-80 is now emulated.
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: Darl181 on October 13, 2011, 07:41:28 pm: A 64*48 screen...0.o

Pretty awesome, now we have all the old cals good to go ;D
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: ralphdspam on October 13, 2011, 08:14:51 pm: Wow! That's awesome! :D
How did he figure out the ASM opcodes?
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: Freyaday on October 13, 2011, 09:39:15 pm: That is amazing.
Now, to the nSpire!/me breaks out his cape
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: NecroBumpist on October 13, 2011, 09:42:00 pm: Wow! That's quite a feat.
I'm very interested to learn how he reverse engineered an instruction set for an undocumented, proprietary processor.

Cheers! To the emulation of Texas Instrument products!

Spoiler For Spoiler:
Omnimaga is blocked at my school as well, under accusations of being a "gaming" website.
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: DJ Omnimaga on October 14, 2011, 01:21:24 am: Someone should try learning 80 ASM to port Wacky Fun Random Numbar Generator v1.000069 to it.

Anyway this is awesome.

Also NecroBumpist Omni is technically a gaming website in some ways. Its calc side is a lot focused on calc gaming and we even have a gaming section and games downloads section. :P
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: TIfanx1999 on October 14, 2011, 07:27:27 am: Wow, this is awesome news to be sure. Wasn't Randy also one of the people involved in hacking the TI-81? I have a TI-80, but not one with a link port. No way to get a ROM dump from it. :/
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: JustCause on October 14, 2011, 09:19:47 am: It's official, the calculator community is just awesome. :)
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: TIfanx1999 on October 14, 2011, 11:38:11 am: Also, it's official: Randy Compton is a freakin BEAST. :D
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: Jim Bauwens on October 14, 2011, 12:03:59 pm: Just plainly awesome :)
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: willrandship on October 16, 2011, 03:55:30 pm: We have emus for all the calcs now!

Edit: Minus CX and other color-nspires, I guess.
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: TI-Over9000 on October 18, 2011, 04:30:21 pm: cool!
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: Munchor on October 21, 2011, 04:56:12 pm: It's impressive to see (as Ryan said on ticalc.org) how some people put a lot of effort in creating emulators for TI calculators. Especially the TI 80, which is nearly forgotten.
Title: Re: Randy Compton releases the first TI-80 emulator
Post by: willrandship on October 30, 2011, 02:54:31 pm: Not to mention having almost nothing in common with the other calcs. It wouldn't have been simple even given the rom easily.