Lumen

[last jungle]

I will make a git later

[rain badger]

Severance?

[last jungle]

?

[rain badger]

Show

[fathom shuttle]

osdev starter pack: limine template

[halcyon breach]

They didntuse the template as stated in chat

[fathom shuttle]

what chat?

[halcyon breach]

#osdev-misc-0 message

[fathom shuttle]

yes... I should know about all the message being sent everywhere

[near grail]

you should

bad on your part if you don't

smh

[fathom shuttle]

mb

[near grail]

so uh, what this

[fathom shuttle]

I'll connect my brain to discord

[near grail]

I just saw thread button and clicked cause bored

[last jungle]

anyway

next step : printing text

[fathom shuttle]

flanterm

osdev starter pack item 2

[last jungle]

my bad

maybe I should make a filesystem driver first

[fathom shuttle]

no

[last jungle]

lmao

[fathom shuttle]

what's the point of having a filesystem if you don't even output anything?

[last jungle]

always start with the starter pack

[near grail]

just write a shitty audio driver and make it just play never gonna give you up on boot

and do nothing else

[last jungle]

shit that's a great idea

[fathom shuttle]

make it read out your logs, instead of printing

port some voice synthesiser

[near grail]

THIS

make it the perfect meme os

actually make it display a single image, the caked up luigi

[fathom shuttle]

but you need to actually use the framebuffer, so just loop nyan cat

[last jungle]

good idea from my friends : make it a python interpreter (without libs)

[near grail]

why without liberals

what did the liberals do

[last jungle]

libraries

[near grail]

[last jungle]

oh nvm

got it

[fathom shuttle]

own them liberals and write nyan cat in that python interpreter

[last jungle]

gotta make myself something to eat first

[bitter reef]

the kernel is very mysterious and important

[rain badger]

its used for microdata refinement

[last jungle]

it has confidential informations

[dim oriole]

the colorful line drawing algorithm

must keep it secure

[last jungle]

now the question is

how am I gonna display text with the framebuffer

[stoic path]

Displaying text isn't too hard

[unkempt breach]

flanterm

and nanoprintf for printf

[stoic path]

Oh yeah, that too lol

[last jungle]

welp that works

I'd like to be lib independant later but for now it does the job

it was actually very simple lol

btw what res is the limine framebuffer ?

[unkempt breach]

?

you can get it from the response

or

set it yourself

[last jungle]

I guess it isn't 1920x1080

[unkempt breach]

the fb response has the values

[last jungle]

let's see now that I can print text 😎

[unkempt breach]

you can set it like this

[last jungle]

or do that

[last jungle]

thanks for the info tho

[last jungle]

https://github.com/dblt-tim/lumen

[last jungle]

now what should I do ?
memory management ?

[last jungle]

first I'm gonna work on a good kprintf implementation

[stoic path]

Do you have a GDT and IDT? (This might be a stupid question but imma ask just in case)

[last jungle]

not yet

[stoic path]

Ah okay, yeah you have to set those up first

[last jungle]

I am still working on my kprintf

then I'll do these

[stoic path]

After you finish that ofc

[last jungle]

hell yeah

[stoic path]

Awesome!

[last jungle]

now time for the GDT and IDT

ok I don't understand anything

that's so cool

maybe I should stop there for today

enough coding

[last jungle]

doesn't limine set them at boot time ?

[stoic path]

Yeah, but they're kind of barebones, the kernel's supposed to set them up itself once it's booted

[last jungle]

oke

[last jungle]

ok I'm lost

my brain doesn't want to understand somehow

I'm pretty sure it's something actually easy

I've been looking there and there and I also asked chatgpt to explain to me

[fathom shuttle]

why don't newbies understand that using llm for this results in literally nothing

it makes your situation works, because you offload your thinking to chatgpt

[stoic path]

I might wanna take a look at the Intel SDM

[last jungle]

I think I am getting it

[last jungle]

if I'm not wrong that's the way

[last jungle]

L: Long-mode code flag. If set (1), the descriptor defines a 64-bit code segment. When set, DB should always be clear. For any other type of segment (other code types or any data segment), it should be clear (0).

does this mean I should set it to 0 for my data seg ?

(sounds stupid but we never know I just wanna be sure)

[stoic path]

I believe so?

[last jungle]

I believe so too

at this point we'll see if it works or breaks lmao

maybe I'm doing shit

programming be like

now I guess I need to do a smol bit of assembly to load the gdt

[last jungle]

yep I'm defo wrong either on the asm or in the gdt

I guess it's not in the gdt itself if I can do lgdt without problems

or is it ?

man idk

[stoic path]

That's not necessarily true, iirc it doesn't really matter what's in the GDTR until you try to reload the Segment Registers (so if you haven't loaded the GDT properly things are gonna go wrong)

Or I suppose a better way of phrasing it is changes in the GDTR don't take affect until the segment registers are reloaded

[last jungle]

because I tried doing that with inline assembly (with as syntax ofc)

[stoic path]

What segments do you have in your GDT?

[last jungle]

code and data

[stoic path]

Also I believe it's recommended to write a assembly subroutine instead of using inline assembly

[last jungle]

null as first entry

[stoic path]

Okay

What's happening when you reload the segment registers?

[last jungle]

the kernel crashes and qemu restarts

also here's the code

[stoic path]

can you give qemu logs? (just use -no-reboot -no-shutdown to make sure it doesn't reboot and -d int to see all interrupts being fired)

[last jungle]

oke

thanks to you I just saw an error in my makefile

I defined my qemu flags in a variable QEMU_FLAGS and it was referenced as QEMUFLAGS so it wouldn't work

[stoic path]

oh, yeah that would be a problem XD

[last jungle]

there's a lot of things

[stoic path]

just send the entire log

[humble abyss]

[last jungle]

uh

it's very long

[stoic path]

you can use pastebin

[last jungle]

nah I'm putting it all in a txt file

[stoic path]

Ah, you're getting a Page fault and then a General Protection Fault

[last jungle]

so it means ?

[stoic path]

Uhh, I don't totally know XD. But my guess is you're loading the GDT wrong

[last jungle]

lmao

thanks for the help tho

[stoic path]

np!

[last jungle]

I'm gonna write it in a separate .asm file

with nasm syntax I guess it should be easier

I just copy pasted what was written in the wiki gdt tutorial page (as long as I understand what I'm writing it's okay ig)

well at least now I know the problem comes from my gdt

[stoic path]

That's a start!

[last jungle]

because the asm should be good now

so the fault comes from the gdt

holy shit it works

I found the problem

find the difference between this :

[last jungle]

and that :

-# I feel very stupid rn

[stoic path]

YAY!

[last jungle]

that's a big hell yeah

now time for the IDT

for now I don't need a more complicated gdt as I'm not going in usermode for now nor dealing with multitasking

[humble abyss]

It's all apart of learning!

[last jungle]

that's why I'm here

problems are the (un)funny part of programming

oh wait no

the problem is still here

-# I feel stupider

-# I didn't look at the window title being "QEMU (paused)"

[stoic path]

oof

I know how that feels

[last jungle]

I think I know where I messed up

gimme a sec

ah

I'm using the whole gdt as the address of the gdt

that's a problem

well that's a thing but qemu still crashes

[last jungle]

seems like my gdtr.base doesn't even have a value

that could be causing the crash

[last jungle]

asked it to print 0 in hex and then the value in hex and it shows me this

so it's not my kprintf impl that is causing a problem

apparently my gdt doesn't have an address

it's not null it's just

im gonna cry

[last jungle]

it was

here's the real one

(0xFFFFFFFF was just for testing)

[stoic path]

yeah, that looks much better

[last jungle]

I might aswell just rewrite my entire gdt code

[last jungle]

BIGGEST HELL YEAH IN LIFE

QEMU DIDN'T PAUSE

WHICH MEANS IT WORKS

IT'S 4:30 AM I CAN FINALLY GO TO SLEEP

[stoic path]

🎉 🎉 🎉

[last jungle]

I crave sleeping

but now I can sleep in peace

[stoic path]

great job!

[last jungle]

and now it's all pushed on github

debug ? ❌
kprintf everywhere 😎

[last jungle]

now I'm gonna work on the IDT

[last jungle]

well that's even more confusing than the gdt

[fathom shuttle]

gdt
idt
confusing

I don't think you're ready for osdev

[last jungle]

but I'll understand

I understood the gdt

[fathom shuttle]

not by not reading

[last jungle]

and I will understand the idt too

[last jungle]

I am reading rn

[fathom shuttle]

reading what?

sdm?

[last jungle]

right now the osdev wiki page

then I'll take a look at the sdm

[uncut void]

I recommend using code formatter if you don't use it already. Makes code look all good lookin

[last jungle]

never thought about it

[uncut void]

Oh and by the way, you can use pre-commit git hook so it automatically formats the code before commiting to the stash

[young crystal]

ew

[uncut void]

What?

[young crystal]

a code formatter

🤮

(/s)

[uncut void]

What's wrong with it?

Ah

Okay

[last jungle]

honestly I like the way I write my code

[uncut void]

Code formatter lets you make it format code how you want

there's also this site:
https://zed0.co.uk/clang-format-configurator/

[young crystal]

I mean I see pretty little need for a formatter. It's not super hard to format clean code yourself as you go.

I get it if it's a project with multiple people where your editors might do different things automatically

but that's not really the case for a personal project

[uncut void]

It's up the Tiwim tbh

if they want they will use it

[last jungle]

for now I don't have a big codebase, even if I wanted to format my code I'd do it by hand

and for now I want to get to work on the isr

wait can I use the interrupt gcc attribute so I can write my handler in C ?

but it also limits my control over it...

meh better do some asm

[young crystal]

you can but I recommend just doing it in asm

[last jungle]

can I make the base of it in asm, and then call a c function for like displaying information ?

[young crystal]

yes

[last jungle]

good

so basically what I need to do is :

• pushad
• call the c func
• popad
• iret
  ?

oh wait

no pushad and no popad in long mode

[young crystal]

yeah

[last jungle]

so I'll have to push all regs myself

[young crystal]

just make a macro to push/pop everything

[last jungle]

I haven't learnt macros in asm yet

oh ok I see

[normal oar]

Its fantastic for projects with many people contributing though i really agree you should format your code from the getgo, otherwise its a pain to read and modify

[last jungle]

by the way for the idt do I need to do something after lidt [idtr] ?

oh yeah

sti

[last jungle]

I think I'm done with the IDT

qemu doesn't crash

[last jungle]

I'm gonna stop there for the week end

[halcyon breach]

if you can get past setting up paging i will officially consider myself dumb

[last jungle]

bet

[last jungle]

ok so right now I have a physical memory allocator ig

time for paging itself

(I didn't work much these last days now I'm back (I think ?) )

[last jungle]

ok it's been some time

I can map and unmap pages now

[uncut void]

@halcyon breach you stupid af gang

[halcyon breach]

what 😭

yes im stupid

i dunno how i coudlnt get past implementing paging

[young crystal]

stfu

most useless comment on a thread

for hobby osdev

don't be a dickhead

[young crystal]

dw paging's hard it took me a little while to get it too, it's easier after the first time you'll learn to love it

[uncut void]

#1367113317184700426 message

I'm not an asshole

[dry delta]

Yep. Takes quite a while to get a good implementation done.
It's one of the first "big" components you write which require following documentation, which is hard if you've never worked with documentation before.

People that get paging done very fast (usually) either:

1. Have done it before
2. Copy pasta from tutorial
3. Have something half working

[young crystal]

yep

[last jungle]

took me a few weeks to get something working

now I'm resting a bit