Once I enable interrupts with sti, I get an exception.
Before I enable IRQs, I first remap the PIC to offsets 0x20 on master and 0x28 on slave; here is the remapping code:
Code:
void irq_remap() {
outb(0x20, 0x11);
outb(0xA0, 0x11);
outb(0x21, 0x20);
outb(0xA1, 0x28);
outb(0x21, 0x04);
outb(0xA1, 0x02);
outb(0x21, 0x01);
outb(0xA1, 0x01);
outb(0x21, 0x0);
outb(0xA1, 0x0);
}
And this is my IRQ-installing code:
Code:
void install_irqs() {
irq_remap();
set_idt_gate(32, (unsigned)irq0, 0x08, 0x8E);
set_idt_gate(33, (unsigned)irq1, 0x08, 0x8E);
set_idt_gate(34, (unsigned)irq2, 0x08, 0x8E);
set_idt_gate(35, (unsigned)irq3, 0x08, 0x8E);
set_idt_gate(36, (unsigned)irq4, 0x08, 0x8E);
set_idt_gate(37, (unsigned)irq5, 0x08, 0x8E);
set_idt_gate(38, (unsigned)irq6, 0x08, 0x8E);
set_idt_gate(39, (unsigned)irq7, 0x08, 0x8E);
set_idt_gate(40, (unsigned)irq8, 0x08, 0x8E);
set_idt_gate(41, (unsigned)irq9, 0x08, 0x8E);
set_idt_gate(42, (unsigned)irq10, 0x08, 0x8E);
set_idt_gate(43, (unsigned)irq11, 0x08, 0x8E);
set_idt_gate(44, (unsigned)irq12, 0x08, 0x8E);
set_idt_gate(45, (unsigned)irq13, 0x08, 0x8E);
set_idt_gate(46, (unsigned)irq14, 0x08, 0x8E);
set_idt_gate(47, (unsigned)irq15, 0x08, 0x8E);
}
Here is IRQ 0 in assembly:
Code:
irq0:
cli
push 0
push 32
jmp stub
This jumps to an assembly stub common to each IRQ:
Code:
stub:
pushad
mov eax, esp
push eax
mov eax, handle_irq
call eax
pop eax
popad
add esp, 8
iret
Which then calls this C handler:
Code:
void handle_irq(struct regs *r) {
void (*handler)(struct regs *r);
handler = irq_routines[r->int_no - 32];
if(handler) {
handler(r);
}
if(r->int_no >= 40) {
outb(0xA0, 0x20);
}
outb(0x20, 0x20);
}
I am somewhat suspicious that the issue is in my register frame, so here it is:
Code:
struct regs {
dword errcode, int_no, ebp, esp, ebx, edx, ecx, eax, esi, edi;
};
Does anyone know what may be the issue?
Thanks
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