RISC-V Assembly Hello World (Part 2)

In this video, we complete our Hello World program in RISC-V assembly. We setup our write syscall and notice how RISC-V offers pseudoinstructions as well as basic instructions.

In case you missed it, Part 1 is here:

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Timestamps:
00:00 Intro
00:28 Adding Secondary System Calls
02:17 Calling the right
03:12 Write() Syscall
04:16 Setting up Arg Registers
05:21 RISCV Specifications Manual
06:56 Size Argument
07:44 RISCV Linux Kernel Syscall Reference
08:46 Running our Program
10:00 Recap

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Links Mentioned in Video:

Risc-V Reference Manual:

Syscall Reference:

Write Manpage:

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[HamzaQayyum]

This tutorial (part 1 and 2) was SO HELPFUL! Completely demystified syscalls for me. I was able to write some small terminal programs that took in input and printed out stuff purely in assembly, which was extremely gratifying. It's rare when you get someone to explain parts of the computing stack with such simplicity and clarity, and, in that respect, your presentation style and production quality is EXCELLENT.
Thank you so much!

[katikistan]

Awesome video, hoping to see more on RISC-V on the channel!

[mkslxkg]

Cool!, thank you Laurie. BTW, i have finished building my RISC-V QEMU development environment.

[NTxC]

Nice vid. And that Fishy tune again, damn earworm.

[artursmihelsons]

Great video! Thanks for reference links in video description! 👍

It's cool to see Tux in background.
By the way, I don't use registers directly, usually, I redefine them with names before for easier writing later. But that's in different assembler. Only, I don't know, is it such option in Vi..

[pacoalsal]

Laurie is going places with these thumbnails.

[chriskiwi]

This is so well explained and useful. Thank you

[btruj]

Thanks for making it easy to understand. (Runs to desktop keyboard to try...)

[ArabVlog]

I love it, 😂😂 hillarious thumbnail, even though i didn't understand a thing, can you daily drive this isa i challenge you to do it

[fcf]

Nicely done,
For the future would be great to have the actual text in a more legible color schema/font; because between the font switching and the color schema switching, at times it is quite uneasy on the eyes :)

[gSys]

I've one question.
I don't know if I missed it in the first episode or just misunderstanding.
You are compiling to the risc v isa but how can just simlpy type "./hello" to execute?
As far as i know you said that your machine is running on an arm chip.
Also the prompt in the terminal says armvm.
So yeah, where is the qemu part? 👀
I dont understand how the execution is even possible 🤔

[Slicudis]

Now it's time to make a tutorial in which system calls are used
Instead, memory mapping is used >:)

[giuseppesec]

it'd be super cool if you got a board like a mango pi mq pro and did some messing with gpio pins in asm

[perpetualrabbit]

I wonder if there is a pseudo instruction or a syntax to get the size of a string that is defined in the data section (.section .data)

[asimami]

Hi Laurie, This is an amazing tutorial and has spurred me into learning more about the RISC-V architecture. I'm currently developing on a macbook using riscv tools and when I run this using the spike emulator it gives me an illegal instruction executed error. Any insights?

[Dygear]

Is there a compiler macro for getting the length of a string from inside a .data section so you don't have to recalc the Len of the string at all call sites each time you change it?

[clamhammer]

What is the point of this exercise? As far as I understand it, it would only be useful if creating a new language taht compiles down to riscv. Correct?

[jacklupino]

nice video, how can I make an input using the keyboard and then display it in the terminal using the risc-v assembly?

[notafbihoneypot]

How to write hello world in assembly in 49min

[AccurateBurn]

laurie hackernews link in bio is broken, userid is missing