I have programmed by looking up op codes in a table on a sheet of paper and entering the hex codes into an EPROM programmer.
Did this in university in the very first week, quite a few people dropped out after that 😅
Fucking ancient. This was for a Z80 based system using discreet logic for addressing and IO, constructed on a wire-wrapped board.
Oh that’s interesting. I started poking around with a Gameboy emulator guide implemented in Python that intended to emulate a Z80. Got any good resource recommendation in case I decide to pick this back up and inevitably get stuck?
If you want some modern day fun with this, try the Zachtronics programming games; TIS-100, Shenzhen I/O, and Exapunks.
Or, my personal favorite I only discovered somewhat recently, try Turing Complete. You start by designing all your logic gates from just a negate gate IIRC. You eventually build up an ALU and everything else you need and then create your own computer. Then you define your own assembly language and have to write programs in your assembly language that run on the computer you’ve designed to complete different tasks. It’s a highly underrated game, although it takes a certain type of person to enjoy.
Another interesting low-level interpreter/emulated system to look into for anyone else trying to get started with this type of thing is the CHIP-8! It’s a pretty basic 8/16-bit instruction set (there are 35 opcodes, the instructions themselves are mostly simple) and there are tons of detailed guides on making one and writing roms for them.
Turing Complete looks really interesting! How polished is it? Just looked it up and saw it was in early access
I would say it’s very polished. It does everything you’d expect and has some nice QoL features. There was work on a big update that’d improve performance and things, but the last information about that was from Aug of last year as far as I can tell. That’s not a big deal though. The game works fine without it.
I once knew somebody who supposedly thought that ASM was high level.
Wait until you learn about micro ops and processor internals. That somebody isn’t as wrong as you think.
It’s a matter of perspective. To someone who’s job is to write the system which interprets ASM, ASM is high level
It’s higher than machine code. It’s degrees of highness. Any abstraction technically makes it high level.
I would argue they don’t know what that means really. Assembly is pretty much a mapping of words to machine code. It’s just a way to make machine code easier to read. It doesn’t actually change how it works.
A compiler re-arranges and modifies things so what you write isn’t the same as the final program that is created. With assembly it is. It’s not really an abstraction, but a translation. It doesn’t move you further from the machine, it only makes it so you’re speaking the same language.
I am once again asking programmers to explain the joke
C was originally created as a “high-level” language, being more abstract (aka high-level) than the other languages at the time. But now it’s basically considered very slightly more abstract than machine code when compared to the much higher level high-level languages we have today.
Other way around, actually; C was one of several languages proposed to model UNIX without having to write assembly on every line, and has steadily increased in abstraction. Today, C is specified relative to a high-level abstract machine and doesn’t really resemble any modern processing units’ capabilities.
Incidentally, coming to understand this is precisely what the OP meme is about.
To add on to @azdle@news.idlestate.org 's comment, “High Level” in terms of programming languages means further away from how the computer processes things and “Low Level” means very similar to how machines process things. For example, binary and hexadecimal (16 bit) machine code such as “assembly language” are both low level.
Imagine if program interpreters were building blocks, then 6 layers of abstraction would be very tall or higher level.
This is pedantic, but assembly languages get “assembled” to machine code. This is somewhat similar to higher level languages being “compiled,” which eventually becomes assembly which gets assembled. The major reason why these are different is because a compiler changes the structure of the code. Assembly is a direct mapping to instructions. It just converts the text into machine code directly, which is why it’s easy to go from machine code to assembly but decompiling doesn’t give you identical results to the original source code.
Also, binary and hexadecimal are just different ways to view the same binary data and aren’t different things. There is only “machine code” which is a type of binary data but you can view binary with any arbitrary base, though obviously powers of 2 work better.
Assembly is a direct mapping to instructions. It just converts the text into machine code directly,
Kinda… yes and no? At least with x86 there’s still things like encoding selection going on, there’s not a 1:1 mapping between assembly syntax and opcodes.
Also assemblers, at least those meant for human consumption (mostly nasm nowadays) tend to have powerful macro systems. That’s not assembly as such, of course.
But I think your “a compiler changes the structure of the code” thing is spot-on, an assembler will not reorder instructions, it won’t do dead code elimination, but I think it’s not really out of scope of an assembler to be able to do those things – compilers weren’t doing them for the longest time, either.
I think a clearer division would be that compilers deal with two sets of semantics: That of the source language, and that of the CPU. The CPU semantics don’t say things like “result after overflow is undefined”, that’s C speaking, and compilers can use those differences to do all kind of shennanigans. With assemblers there’s no such translation between different language semantics, it’s always the CPU semantics.
When I learnt programming (back in early 2000s) the textbook said C is a high level 3rd generation language with 4th gen languages being something higher (I don’t remember what examples were given specifically). This is back when the java applets and action script for flash were the hot things. How I miss the days without the world being cursed by JS.
I think C was 2nd, 3. is Java and Python, 4 SQL and 5th would be some hypothetical AI instruction language?
1st level is direct binary code as was done with punch cards. Assembly language is a 2nd level language. C is a level above, thus it’s level 3.
When the gp’s book says that C is a third generation language: I would guess the first generation is Fortran and the second generation contains ALGOL and BCPL. C was heavily influenced by BCPL. (get it? C comes after B)
I mean, C is a high level language? Now, sure, C isn’t a super expressive language and every C statement compiles to very few assembly instructions comparatively speaking, but it has a whole lot of stuff that assembly doesn’t have. Like nice loops and other control structures and such, and not worry about which processor registers are used.
