isr.c

//
// isr.c -- Handle level interrupt service routines and interrupt request handlers.
// Code from JamesM's kernel developement tutorials
//

#include "common.h"
#include "isr.h"
#include "monitor.h"

isr_t interrupt_handlers[256];

// This gets called from our ASM interrupt handler stub.
void isr_handler(registers_t regs)
{
    if(interrupt_handlers[regs.int_no] != 0)
    {
        isr_t handler = interrupt_handlers[regs.int_no];
        handler(regs);
    }
    else
    {
        monitor_write("recieved interrupt: ");
        monitor_write_dec(regs.int_no);
        monitor_put('\n');
    }
}

// This gets called from our ASM interrupt handler stub.
void register_interrupt_handler(u8int n, isr_t handler)
{
    interrupt_handlers[n] = handler;
}

// This gets called from our ASM interrupt handler stub.
void irq_handler(registers_t regs)
{
    // Send an EOI (end of interrupt) signal to the PICs.
    // If this interrupt involved the slave.
    if(regs.int_no >= 40)
    {
        // Send the reset signal to slave.
        outb(0xA0, 0x20);
    }
    // Send reset signal to master. (As well as slave, if necessary).
    outb(0x20, 0x20);

    if(interrupt_handlers[regs.int_no] != 0)
    {
        isr_t handler = interrupt_handlers[regs.int_no];
        handler(regs);
    }
}