NoName OS 25.07.2006

[FlashBurn]

In the attached zip is an iso image and it would be good if you could burn and test it on a real pc (uni and smp systems) and say what it writes to the screen and then also give some info about your sys!

[octavio]

I tested it ,the message on the screen was something like:
apic not supported press enter to reboot

The cpu is a PIII 933Mhz.

[FlashBurn]

Oh, then your BIOS deactivates your cpu?s apic. Then problem is that my OS relies on an apic Maybe you have an option in your bios for enabling the apic of the cpu?

I tried to support both apic and pit, but I have failed

Ok, and here is a new version, which uses ACPI (if available) to detect the number of cpus and io-apics!

[octavio]

Now i have tested the latest version on a atlon xp1800 with the same result, and the bios dont have a option to disable acpi or apic.

[FlashBurn]

This is strange! The apic is in the cpu since the pentium (I think so) and I also changed because of that my board, because the bios also deactivated the apic

You needn?t to deactivate acpi (and you can?t) it is only used for detecting cpus and io-apics if it is not available I use the mps.

I have not to understand the reasons for this!

The problem is that I have 1 kernel and this kernel is able to work on uni and smp systems and if I use the apic on both systems it is easier for me to code.

Edit::

Tomorrow I will have time, so maybe I will give it a try and write some code to support pcs w/o apic enabled. But the last time I tried it, it didn?t work

[gaf]

Hello Flashburn,
you do know that the local APIC can get reactivated on all chips from pentium 54 onwards ? It's actually even described in the latest version of the Intel Manuals (volume 3, chapter 8.4.3): All you have to do is resetting a bit in one of the MSRs that was cleared by the BIOS. There's also some linux source available..

It's by the way quite common that the BIOS deactivates the local APIC on uniprocessor machines. This only changed wih the latest generation of CPUs (pentium 4+), and even there you can't really rely on it.

regards,
gaf

[FlashBurn]

I will have a look at this, but I think the problem was that there are 2 methods to deactivate the apic and one method can?t be undone!

In other news I fixed some bugs in the slab allocator and a bug in the gdt code and now my os support up to 255 cpus (in theory, because I can only test it with qemu).

[FlashBurn]

I reread the intel manual and I think I understood something wrong and now I activate the apic and then check for it. The problem is that I have no pc where the apic is deactivated and so I need someone who can test the new code!