[mksaunders]

Commodore 64, sure, but I wouldn't recommend the Atari 2600 for beginners! I wrote a small game for the 2600 years ago, and it's a tricky little machine. It doesn't even have a video frame buffer, so you have to do things on the fly, depending on which line of the screen is being beamed (think of old-school CRTs).

Indeed, a whole book was written about it: https://en.wikipedia.org/wiki/Racing_the_Beam

The 2600 is fascinating and fun to code for, but for asm newbies I'd recommend the C64 or NES...

[klodolph]

Or perhaps the GBA, which is modern enough to have a framebuffer, but old enough that the framebuffer is just sitting there at a known address.

[zeta0134]

I can additionally recommend the GBA as an interesting fixed target. Lots of folks recommend an Arduino for this, and those are great little machines, but they have two problems. 1. they can be a bit too limited for a lot of potential projects, and 2. because they are hardware projects boards, they don't do very much on their own. Figuring out what to hook them up to is half of the fun, but it can be a daunting choice for a beginner, especially someone learning assembly language for the first time.

The Gameboy Advance is a marvelous little platform. It runs a modified ARM7, so if you learn its machine language a lot of that knowledge will transfer into the industry. It runs at a brisk 16 MHz, which is fast enough that it can run compiled C code quite comfortably, but slow enough that performance still matters very much once you try to push the system's limits. Even if you run it in C rather than assembly (perhaps ideal for a true beginner), the whole machine is chok full of bare-metal standbys. Most of the graphics and sound hardware is memory mapped, requiring very specific bit patterns written to special addresses to tell the rest of the hardware what to do. Working with graphics requires an understanding of interrupts and synchronization. Finally, being a games system with a screen, buttons, and a speaker built in, there's a lot of projects you could build... but the easiest is to make a game! And what a blast that system is to make games for. Powerful enough to do all sorts of compelling things, but simple enough to program (even as a beginner) that you can easily have backgrounds and sprites onscreen in about a day of effort.

[deepaksurti]

GBA = Game Boy Advanced

[AlexCoventry]

I learned assembly on a TRS-80 Color Computer (6809 CPU.) Interactions with the machine were fairly straightforward.

[Sindisil]

The 6809 was a joy to program in assembly language. I enjoyed some aspects of Z80, and loved the puzzle of getting things done with 1802 and 6502, but 6809 was, for me, the sweet spot.

[osullivj]

Two stack pointers, one for call/return, the other for push pop data.