Having some trouble with my multitasking system

[Pyrofan1]

Okay, so i rewrote my entire Tasking code with the suggestions you made, but it just freezes.
i've attached my code

[t0xic]

I would suggest writing the code in assembly. Theres still a lot you are missing. Re-read the links. Just use some assembly (not inline, as gcc chooses which registers to use).

Also, I know the string declaration is legal and not related to the problem, but it's always better to use a safe method anyways. (better safe than sorry)

[Pyrofan1]

I think i have the problem nailed. The iret skips over the code that acknowledges the interrupt which explains why it freezes.
Now i've added this code

Code: Select all

out $0x20, $0x20

But GAS chokes on it with Error: suffix or operands invalid for `out'
And unless i'm mistaken that is proper syntax.

[bewing]

Ah, sorry, no.

Either the port number has to be in DX, or the value has to be in AL. You cannot use immediates for both values at the same time.

[Pyrofan1]

this doesn't work either

Code: Select all

mov $0x20, %dx
out $0x20, %dx

[t0xic]

try putting 0x20 into both al and dx. and doing 'out dx, al'

[Pyrofan1]

that didn't work either

[bewing]

The out instruction may not use proper AT&T syntax.

Try ALL of the following:

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mov $0x20, %al
out $0x20, %al

mov $0x20, %dx
out %dx, $0x20

mov $0x20, %al
out %al, $0x20

Oh, and don't you have to put out.b in stupid AT&T syntax? Does it default to byte size?

And then write a nasty email to the gcc people, and tell them to drop the stupid AT&T syntax, and switch to nice intel syntax. Or turn on the intel syntax asm flag in gcc.

[t0xic]

or just link in nasm files

[Brynet-Inc]

Simple:

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movb <data>, %al
outb %al, $0x20

It's logical, mov "source" to "destination" - unlike the unappealing look of mov "dst" to "src".

bewing, stop attacking the syntax... it's pretty.

Code: Select all

out $0x20, $0x20

But GAS chokes on it with Error: suffix or operands invalid for `out'
And unless i'm mistaken that is proper syntax.

The out instruction doesn't support 2 immediate operands, regardless of the syntax.

If you use an immediate operand for the IO address, you'll have valid range of 0 to 0xff, otherwise, use the dx register.

[Combuster]

The key thing is that you need to suffix b/w/l on the out to make it work.
i.e. use outb, outw or outl (as Brynet-Inc did)

It's logical, mov "source" to "destination" - unlike the unappealing look of mov "dst" to "src".

bewing, stop attacking the syntax... it's pretty.

You're starting a holy war here. Many people are more comfortable with dst = src over src = dst notation.

[Brynet-Inc]

You're starting a holy war here. Many people are more comfortable with dst = src over src = dst notation.

Alright alright.. apologies.

[bewing]

Heh. I was just kidding.

And intel syntax is not dest = src, is is "register/address being modified, data". It is a small philosophical difference, that leads to a different paradigm. I just think that extraneous punctuation is the farthest thing from "pretty". And in this particular case (assuming -- as is reasonable -- that Combuster is right), it is precisely that extraneneous punctuation that caused Pyrofan1's code to fail. This is Not a Good Thing.

[Brynet-Inc]

Heh. I was just kidding.

And intel syntax is not dest = src, is is "register/address being modified, data". It is a small philosophical difference, that leads to a different paradigm. I just think that extraneous punctuation is the farthest thing from "pretty". And in this particular case (assuming -- as is reasonable -- that Combuster is right), it is precisely that extraneneous punctuation that caused Pyrofan1's code to fail. This is Not a Good Thing.

I meant from a visual perspective.

mov eax, 5 for example, could look very confusing to a beginner...

I guess now that I think about it more.. from the eyes of someone deeply intimate with the "mv" command, it's scary, but from a C programmer it's simply "var = 5".

I'll just shut up now... resist the urge to purge

[Brynet-Inc]

.And in this particular case (assuming -- as is reasonable -- that Combuster is right), it is precisely that extraneneous punctuation that caused Pyrofan1's code to fail. This is Not a Good Thing.

Whoops, I missed this portion of your reply..

That's incorrect, I only included the suffixes for added clarity... habit.

Code: Select all

movb $0x20, %al
outb %al, $0x20

and

Code: Select all

mov $0x20, %al
out %al, $0x20

Are valid syntax, producing the same object code..