After 41 years, my first assembly program on my first computer, the Tomy Tutor

http://oldvcr.blogspot.com/2024/03/after-41-years-my-first-assembly.html

by goldenskye • 2 years ago

145 26 2 years ago

oldvcr.blogspot.com

joeyhage• 2 years ago

Interesting how the connotations of parent guidance have changed over the years. It’s pretty rare these days to see “no parental guidance necessary.”

bitwize3• 2 years ago

Cool! I just wrote my first assembly program for the TI-99/4A, and am working on a TMS9900 assembler.

classichasclass• 2 years ago

(author) I thought AS worked pretty well. The syntax is a little idiosyncratic but it "just worked" once I learned its pet peeves, and it seems to have specific support for the added 9995 instructions.

bitwize3• 2 years ago

I used AS to write the program, and it is my "reference assembler" for the one I am writing. I just wanted to see if I could write a working retro assembler.

cpswan• 2 years ago

Have you found your way to Stuart Conner's page? http://www.stuartconner.me.uk/

Lots of resources on the original TI dev boards and tools for TMS99Xx.

bloaf• 2 years ago

I believe my first "computer" could have been the toy version of the Tomy Tutor:

https://www.nostalgianerd.com/tomy-tutor/

begueradj• 2 years ago

The title alone speaks to me. Thank you for the article.

tcbawo• 2 years ago

The backstory of the Tomy Tutor is interesting. This seems like it was a tremendous longshot, financially. It’s hard to imagine how this would be greenlit in today’s age. There are so many weird architectures of the 1980s — I appreciate the quirkiness and diversity.

hvs• 2 years ago

The home computer boom of the 70's and early 80's was the product of cheap microprocessors entering the market in the 1970's (chiefly the 6502 and Z80). In some cases it was scrappy startups (e.g. Apple) and in others it was an attempt to get in on the gold rush. There were no "standards" yet; IBM had yet to enter the fray, and when it finally did in 1981 it was still way too expensive for most of the home market, so wasn't really a factor for years.

So the way to think about this period is like the Internet boom of the late 90's or the AI gold rush of today. Things got greenlit because no one quite knew what would be successful (frankly, most companies/people struggled to find a use for the 8 bit machines besides gaming, which is a hard sell to a lot of parents). The quirkiness of the architectures is a direct result of the industry being the Wild West. You wouldn't see it today because the industry has been established.

onetimeuse92304• 2 years ago

Not sure it was hard sell. The computers were expensive but people knew they are the future. Parents who could afford it would buy it for the kids just to have access to the computers without knowing what good they are for.

RetroTechie• 2 years ago

A shame those TMS99xx were limited so severely by design of the systems they were in. Seems like a decent CPU family, and with proper 16-bit bus + enough RAM could have made for nice contenders in the home computer market.

But 256 byte scratchpad RAM, 16K accessible only through the videochip (and not from BASIC!?!), in 1983? Too little too late, regardless of price. C64's, ZX Spectrums etc were everywhere by then. Much more capable and not that expensive.

leke• 2 years ago

Oh wow, I remember these, barely. I never used one though.

jecel2• 2 years ago

The TMS9900 was made in I²L bipolar technology, not MOS. Texas Instruments also had a 4 wide bitslice using the same fabrication process.

adrian_b• 2 years ago

You must confuse TMS9900 with other TI integrated circuits, perhaps those used for TMS990.

TMS9900, which was 16-bit CPU in a big 64-pin package (like that used later by Motorola MC68000) was certainly made in an NMOS technology.

See e.g. Wikipedia:

https://en.wikipedia.org/wiki/TMS9900

There is no doubt about this because TMS9900 required -5 V (for substrate bias), +5 V and +12 V (for enhancement MOS load transistors), like all early NMOS ICs, e.g. Intel 8080. No bipolar technology would have needed such power supplies.

The later TMS9995 was also made in an NMOS technology, but in a more modern variant with depletion transistor loads, which required only a single +5 V power supply, like Zilog Z80 and other more recent NMOS CPUs.

jecel2• 2 years ago

You are correct as is the other reply to my post. The chip in chapter 3 of the 1977 "The Bipolar Microcomputer Components Data Book" from Texas Instruments is the SBP9900 processor, not the TMS9900. I had never noticed this detail before and always had used this book as my reference for the 9900.

nonamesleft• 2 years ago

SBP9900 is the I²L version, found atleast in older M1 Abrams:

https://www.eevblog.com/forum/projects/reverse-engineering-a...

octopusRex• 2 years ago

Bless this guy's parents.

thibaut_barrere• 2 years ago

Me a couple of days ago:

https://twitter.com/thibaut_barrere/status/17711464663602670...

I am really grateful!

MaysonL• 2 years ago

60 years ago, I never got to debug my first assembly program, which had 1 syntax error and an unknown number of bugs, because NASA launched a weather satellite, data from which monopolized the 7090 which the high school enrichmment program was having programs run on. Still rankles a bit.

nobodyandproud2• 2 years ago

I’ve recently been disillusioned in my admiration for NASA.

How NASA used a child math prodigy back in the 1970s: “ At that time, I led my life like a machine – I woke up, solved the daily assigned equation, ate, slept, and so forth. I really didn’t know what I was doing, and I was lonely and had no friends.”

Career scientists and engineers using a kid like this? Pretty scummy in my book.

Compare that to how Srinivasa Ramanujan was treated nearly a century earlier by the British.

Sadly, your schools’s computer time wouldnt have made anyone blink.

npteljes• 2 years ago

If it's the British and the treatment of the brilliant people, the story that comes to mind is of Alan Turing.

https://en.wikipedia.org/wiki/Alan_Turing#Homosexuality_and_...

ngcc_hk• 2 years ago

Very interesting article, but the architecture seems quite odd. And the journey to cut to japan and back not helping. Still like second extinction, it showed the variety when you think odd. It also asked my earlier question about zero page architecture… lately the idea of having large cache under amd might be another evolutionary path btw.

OhMeadhbh• 2 years ago

I just realized I have a 9995-based Tomy Tutor in my closet. Now that I know about this project, I'll have to dig it out. FWIW, for the two years I lived in Richardson, TX, I drove by TI mainside every day to get to work. I eventually remembered how much fun 9900 assembly was and got the vanity plate BLWP [Branch and Load Workspace Pointer], one of the most unique 9900 instructions.

After 41 years, my first assembly program on my first computer, the Tomy Tutor

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