Strange letter displays before string [ACTUALLY SOLVED]

[DixiumOS]

I made my own simple print string routine, hosted on https://github.com/NunoLava1998/DixiumOS-1 (First commit)

However, when i try to run this in QEMU, a phantom monochrome S appears before my text:


How would i fix this unexpected character?

[bzt]

How would i fix this unexpected character?

Debug your code and find the instruction that puts it there. Then modify your source to avoid that.

[Octacone]

I don't like the way your code works. You should have two separate functions: one for printing characters and one for printing characters at a certain position. Your clear screen functions is really really bad, the most unoptimized function ever. Tomorrow I am going to make a GitHub account and edit your repository a bit and help you with your OS + commentary included. Try printing that string without calling your clear screen function.

[DixiumOS]

I don't like the way your code works. You should have two separate functions: one for printing characters and one for printing characters at a certain position. Your clear screen functions is really really bad, the most unoptimized function ever. Tomorrow I am going to make a GitHub account and edit your repository a bit and help you with your OS + commentary included. Try printing that string without calling your clear screen function.

writechar is different than writestring:

Write char writes a character at the specified foreground, background, x position, y position.
Write string uses write char to write a string using the same technique as used in the Bare Bones tutorial. Both can print characters at a certain position, but one writes strings and another writes characters.

[iansjack]

You never write to the top left of the screen (row 0, column 0), so what appears there ("S") is what was left over from the BIOS.

All the same, an improvement on your previous efforts.

[DixiumOS]

You never write to the top left of the screen (row 0, column 0), so what appears there ("S") is what was left over from the BIOS.

All the same, an improvement on your previous efforts.

Thank you.
I also moved the string to 40, 10 and it displayed fine but that S was still there.
I'll make a terminal_init that clears the screen and that S.

EDIT: It doesn't clear. Must be a problem in my putchar.

[hannah]

You never write to the top left of the screen (row 0, column 0), so what appears there ("S") is what was left over from the BIOS.

All the same, an improvement on your previous efforts.

Thank you.
I also moved the string to 40, 10 and it displayed fine but that S was still there.
I'll make a terminal_init that clears the screen and that S.

EDIT: It doesn't clear. Must be a problem in my putchar.

Push my pull request

[iansjack]

Debug your code and find the instruction that puts it there. Then modify your source to avoid that.

None of the OP's code puts the character there. More to the point - look at the code and see why it doesn't write to that location.

[DixiumOS]

You never write to the top left of the screen (row 0, column 0), so what appears there ("S") is what was left over from the BIOS.

All the same, an improvement on your previous efforts.

Thank you.
I also moved the string to 40, 10 and it displayed fine but that S was still there.
I'll make a terminal_init that clears the screen and that S.

EDIT: It doesn't clear. Must be a problem in my putchar.

Push my pull request

Pushed it. I think i'm unpushing it (code is wrong, various things are undefined and many things are defined for no reason and then never used, and the types in 2 functions don't even exist.)

[Octocontrabass]

Hmm.

Any particular reason you created a new account, NunoLava1998?

[DixiumOS]

Hmm.

Any particular reason you created a new account, NunoLava1998?

I want to start over again.

And good news, i got it working (i had to change (y * 80 + x) to (y * 80 + x - 1)).

Got it working, thanks everybody!

https://github.com/NunoLava1998/DixiumO ... inal/tty.c

[Octocontrabass]

And good news, i got it working (i had to change (y * 80 + x) to (y * 80 + x - 1)).

You didn't fix it, you just added a second bug that hides the first bug.

[DixiumOS]

And good news, i got it working (i had to change (y * 80 + x) to (y * 80 + x - 1)).

You didn't fix it, you just added a second bug that hides the first bug.

So... what bug?

It works perfectly fine on QEMU and seems logical:

[Octocontrabass]

This bug.

[DixiumOS]

This bug.

That isn't a bug. If i didn't add that line, only the last char would display in the specified x and y like i used putchar.

Besides, here's another image demonstrating it works: