After 41 years, my first assembly program on my first computer, the Tomy Tutor (opens in new tab)

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.

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.

Me a couple of days ago:

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

I am really grateful!

(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.

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.

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.

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

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