Comment by flohofwoe
1 year ago
IMO It depends a lot on the assembly flavour.
The best ISA for learning is probably the Motorola 68000, followed by some 8-bit CPUs (6502, 6809, Z80), also probably ARM1, although I never had to deal with it. I always thought that x86 assembly is ugly (no matter if Intel or AT&T).
> It quickly becomes tedious to do large programs
IME with modern tooling, assembly coding can be surprisingly productive. For instance I wrote a VSCode extension for 8-bit home computers [1], and dog-fooded a little demo with it [2], and that felt a lot more productive than back in the day with an on-device assembler (or even typing in machine code by numbers).
[1] https://marketplace.visualstudio.com/items?itemName=floooh.v...
[2] https://floooh.github.io/kcide-sample/kc854.html?file=demo.k...
Oh nice, I was talking just yesterday how I liked chips as a programming paradigm.
I agree about tooling, I made a pacman game in a dcpu16 emulator in a couple of days.
I experimented with a fantasy console idea using an in-browser assembler as well. https://k8.fingswotidun.com/static/ide/
I think you can build environments that give immediate feedback and the ability to do real things quickly in ASM. I would still recommend moving swiftly on to something higher level as soon as it started to feel like a grind.
Sure, but learning an old ISA can leave you with a very very wrong idea about how modern processors work. Even x86 assembly paints a very misleading image of how modern processors actually work. For example, someone learning x86-64 assembly will likely believe all of the following:
- assembly instructions are executed in the order they appear in in the source code
- an x86 processor only has a handful of registers
- writing to a register is an instruction like any other and will take roughly the same time
- the largest registers on an x86 processor are 64-bit
All of which are completely irrelevant implementation details hidden behind the ISA. The x86-64 ISA promises execution of instructions in the specified order, a certain number of registers, etc. and that's all they need to know.
The claim is that learning assembler first will build a better intuition about the inner workings, and thus performance, of the processor.
The reality is that any assembler simple enough to be taught as your first contact with programming will leave you with a wrong intuition about how modern processors work, and thus a wrong intuition about the relative performance of various operations.
Having no intuition about something is better than building a bad intuition, especially at the beginning of your learning journey.
> The x86-64 ISA promises execution of instructions in the specified order
It doesn’t, and out-of-order CPUs don’t do that. https://en.wikipedia.org/wiki/Out-of-order_execution: “In this paradigm, a processor executes instructions in an order governed by the availability of input data and execution units, rather than by their original order in a program.”
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They will be disabused of any of those notions simply by reading the relevant portions of the architecture handbook. In a pedagogical environment that's very simple to arrange.
Someone who is just learning to program will not be well served by reading a modern CPU architecture handbook. It is far too complex for someone who doesn't even know yet what a graph is, for example.
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Peeking under the hood is a later step after getting comfortable with assembly coding. E.g. none of those details are really relevant when starting out, instead it makes a lot of sense to do a speed run through computing history in order to really understand why modern CPUs (and computers as a whole) work like they do.
I agree that M68k is nice, as are the 8-bit ones you mention. I just find it strange that you like Z80 and dislike x86 - they are fundamentally not that different and both are descended from 8080.
Yeah the Z80 instruction set is quite messy (mainly because it had to fill gaps of the 8080 instruction set for backward compatibility). But as an evolution of the 8080 instruction set, the Z80 is still cleaner than x86 (IMHO!).
Also, the Z8000 looks quite interesting and like the better 16-bit alternative to the x86, but it never took off: https://en.wikipedia.org/wiki/Zilog_Z8000