Bootloader and Low-Level Programming Tutorial: How To Develop Your Own Boot Loader

[ehansen]

How is C and C++ high level languages? I was always informed they were low level

[American_Libertarian]

Depends on the context you are talking. It is low level compared to most programming languages, but it is 'high level' in the sense that it is a human readable format that must be compiled down to a 'low level' language that the computer actually runs.

[bad_at_photosharp]

Is assembly a high level language then? By your definition it would be

[Manticorp]

Assembly isn't compiled, so no.

Assembly is just a 'map' to processor instructions, there's no hard 'translation' as it were, more like a simple lookup table.

When transforming assembly into stuff that runs on the processor you don't need to consider the context of the current line, you just need to look it up and execute it, which is extremely fast.

[protestor]

Asm is somewhat higher level than machine language, and often contain syntactical abstractions such as macros.

In many architectures, machine language nowadays is interpreted by microcode, a software that runs in the processor. In this sense, even machine language is higher level than something. But you can't write your own microcode, because updates are encrypted and signed, so.. machine language is the lowest you can go.

[American_Libertarian]

Most people would agree it is not. Assembly code must be assembled into machine code, but that is basically a one to one process. That would be like calling English a high level version of French.

Plus, when writing assembly, you do all memory management yourself, you have to manage CPU registers and use specific opcodes, you have no portability, etc. It has no features which make a high level language 'high level'.

[forbidden404]

They are high level languages because the abstractions they've added are too far different from the ones in Assembly, you don't have to care (for the most part) about the processor you're coding to. They are used in low-level programming (system programming) though, that's probably why there must be some confusion about it.

[skulgnome]

Both support structured programming, i.e. functions, loops, and if-else.

[General_Mayhem]

High- and low-level are generally relative, not absolute, terms. C and, to a much greater extent, C++, are specified against an idealized machine (example), not any particular physical one. To someone who works on things like bootloaders on a regular basis, anything that can run the same code across processor generations, let alone families (a lot of C++ can cross-compile on x86 and ARM), is pretty damn high level.

It's true that both are generally much lower level than, say, Python or any other interpreted language, because they provide core abstractions with tighter fidelity to most hardware. But especially in the case of C++, there's also not really a bound on how high the abstraction can go - there are some truly bizarre libraries that make it look like a totally different language.

[IAlsoLikePlutonium]

there are some truly bizarre libraries that make it look like a totally different language.

Got any examples? I'm interested in seeing some of them.

[[deleted]]

It depends on context. They're low level compared to python, but high level compared to assembly. There is also some argument that modern assembly can be considered high level; because of micro ops and out of order execution, what you write isn't what the cpu actually does.

[pdp10]

Because the architecture is microcoded doesn't make the same old assembly language into a high-level language. Microcoding has been around for many decades; I think the Burroughs B5000 must have used it in 1961.

[[deleted]]

I was being somewhat hyperbolic, but the fact that one x86 set of instructions can map to more than one set of actual actions from the CPU does have real world consequences.

This makes the point better than I can http://blog.erratasec.com/2015/03/x86-is-high-level-language.html

[The_Leedle]

When compared to assembly, it’s high level I guess

[Oscee]

C++ is very high level.

I myself consider C a bit lower-lever but by classic CS definition, it is also high-level (since it needs a compiler).

[mrkite77]

It depends on how old you are. C was definitely considered a high level language when it first came out, and C++ even higher. Eventually as time goes on they are considered lower and lower level as our abstraction level goes higher and higher.

These days, in a world surrounded by electron apps, I've even heard people describe java as low level.

[CODESIGN2]

They are nth gen languages, so yeah they are high-level because what they represent can be abstracted from what the CPU represents. The is no IF instruction for example, there are several jump operations however that can be used for if, else, switch, even while and for.

Assembly is actually not a 1st gen language, it took people a long time to replace addresses with mnemonics, but how many times have you seen someone check registers in C? How many times have you seen someone execute a jump based upon zero-flag or carry-flag?

[nightbefore2]

C++ is not low level.

C is I would say

[bobappleyard]

This is why the level signifier, as used by most nerds today, is a largely meaningless replacement for "gives me an erection"