#include <stdio.h>
#include "pic.h"
#include "irq.h"
#include "idt.h"

/* These are own ISRs that point to our special IRQ handler
*  instead of the regular 'fault_handler' function */
extern void Irq_0();
extern void Irq_1();
extern void Irq_2();
extern void Irq_3();
extern void Irq_4();
extern void Irq_5();
extern void Irq_6();
extern void Irq_7();
extern void Irq_8();
extern void Irq_9();
extern void Irq_10();
extern void Irq_11();
extern void Irq_12();
extern void Irq_13();
extern void Irq_14();
extern void Irq_15();

/* This array is actually an array of function pointers. We use
*  this to handle custom IRQ handlers for a given IRQ */
void *IrqRoutines[16] =
{
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0
};

/* This installs a custom IRQ handler for the given IRQ */
void IrqInstallHandler (int irq, void (*handler)(_RegsStack32 *r))
{
      IrqRoutines[irq] = handler;
}

void IrqUninstallHandler (int irq)
{
      IrqRoutines[irq] = 0;
}



/* We first remap the interrupt controllers, and then we install
*  the appropriate ISRs to the correct entries in the IDT. This
*  is just like installing the exception handlers */
void IrqInstall()
{
      PicRemap(32,40);
      
      IdtSetGate(32, (unsigned)Irq_0, 0x08, 0x8E);
      IdtSetGate(33, (unsigned)Irq_1, 0x08, 0x8E);
      IdtSetGate(34, (unsigned)Irq_2, 0x08, 0x8E);
      IdtSetGate(35, (unsigned)Irq_3, 0x08, 0x8E);
      IdtSetGate(36, (unsigned)Irq_4, 0x08, 0x8E);
      IdtSetGate(37, (unsigned)Irq_5, 0x08, 0x8E);
      IdtSetGate(38, (unsigned)Irq_6, 0x08, 0x8E);
      IdtSetGate(39, (unsigned)Irq_7, 0x08, 0x8E);
      IdtSetGate(40, (unsigned)Irq_8, 0x08, 0x8E);
      IdtSetGate(41, (unsigned)Irq_9, 0x08, 0x8E);
      IdtSetGate(42, (unsigned)Irq_10, 0x08, 0x8E);
      IdtSetGate(43, (unsigned)Irq_11, 0x08, 0x8E);
      IdtSetGate(44, (unsigned)Irq_12, 0x08, 0x8E);
      IdtSetGate(45, (unsigned)Irq_13, 0x08, 0x8E);
      IdtSetGate(46, (unsigned)Irq_14, 0x08, 0x8E);
      IdtSetGate(47, (unsigned)Irq_15, 0x08, 0x8E);
}

// Default IRQ handler, launches other handler if installed.
// Also sends end-of-interrupt messages to PIC
void IrqHandler (_RegsStack32 *r)
{
	/* This is a blank function pointer */
      void (*handler)(_RegsStack32 *r);
      
    /* Find out if we have a custom handler to run for this
    *  IRQ, and then finally, run it */
      handler = IrqRoutines[r->int_no - 32];
      if (handler) handler(r);
      
    /* If the IDT entry that was invoked was greater than 40
    *  (meaning IRQ8 - 15), then we need to send an EOI to
    *  the slave controller */
      if (r->int_no >=40) outportb(0xA0, 0x20);
      
    /* In either case, we need to send an EOI to the master
    *  interrupt controller too */
      outportb(0x20, 0x20);
}