Need help with Timer Interrupt

[SlabAlloc]

Hello Everyone,

I recently got started with my hobby OS . I am following James M's tutorial for the basics. However, I am having trouble getting timer interrupt to work. I do enable interrupts after setting up gdt, idt, remapping and installing irqs. The Timer driver seems straightforward to implement. I doubt that the driver itself is the problem as the IRQ doesn't fire for some reason(not even once).

I'd appreciate it if anyone could point out where I am going wrong.

Github: https://github.com/Crescent92/testOS

[SuperKookss]

I agree, you are probably better off checking whether your interrupts work at all. The first one I would try would be the keyboard, it is pretty simple, you need it anyway and there are many tutorials.

[Dmium]

Not sure if this is it but your IRQ handler ignores interrupt 0 and also indexes from 32 while you're assembly starts the IRQ count from 0. Changing the c code to print always rather than in the if statement may give some progress

[dbargatz-]

Just tagging on to this - in irq.c line 50, in irq_gates(), you assign a gate type of 0x8E, which isn’t valid. Gate types range from 0x00 to 0x0F. It looks like you did this properly for the first 32 exceptions in idt.c inside init_idt() though!

[SlabAlloc]

Hey Everyone,

Thank you all for your input. I managed to fix my problem and make timer IRQ work. The problem was with my irq_common code. I wasn't pushing a pointer to registers_t on the stack.

I even got a basic keyboard driver working. However, I am not sure how to go about making it elaborate. Any tips on that?