#include "mt_os.h"
#include "mt_thread.h"
#include "mt_vm.h"


/*
 *  Initialize data structures for mt_os, such as page tables etc.
 */
void mt_initialize()
{
}


/* Clock tick -- gets called after every CLOCK_INTERVAL-instructions.
 * This simulates preemption for the user level program.  interrupts
 * are enabled ONLY on entry into minithread functions.  We do NOT
 * want interrupts occuring during mipsi's execution.  As a result,
 * remember to disable interrupts when switching to a new thread when
 * first entering that thread.
 */
void mt_os_tick()
{
    enable_interrupts(); 	
    mt_minithread_yield();
    disable_interrupts();	/* re-entering mipsi */
}

/* Dispatch mt_os system calls and TLB-related exceptions to the
 * appropriate service routines.
 */

int mt_syscall(unsigned num,
	       unsigned arg1,
	       unsigned arg2, 
	       unsigned arg3) 
{
    int retval;

	if (num == MT_TLB_TRANSLATE_FAULT)
		return mt_tlb_translate_fault(arg1);
	if (num == MT_TLB_WRITE_FAULT)
		return mt_tlb_write_fault(arg1);

    enable_interrupts();
    
    switch (num) 
    {
      case MT_MINITHREAD_FORK:  
	retval = mt_minithread_fork(arg1,arg2); break;
      case MT_MINITHREAD_SELF:  
	retval =  mt_minithread_self(); break;
      case MT_MINITHREAD_DIE:
	retval =  mt_minithread_die(); break;
      case MT_MINITHREAD_YIELD:
	retval =  mt_minithread_yield(); break;
	
      case MT_SEMAPHORE_CREATE: 
	retval =  mt_semaphore_create(); break;
      case MT_SEMAPHORE_INITIALIZE: 
	retval =  mt_semaphore_initialize(arg1,arg2); 
	break;
      case MT_SEMAPHORE_DESTROY:
	retval =  mt_semaphore_destroy(arg1); break;
      case MT_SEMAPHORE_P:
	retval =  mt_semaphore_P(arg1); break;	
      case MT_SEMAPHORE_V:
	retval =  mt_semaphore_V(arg1); break;
	
      case MT_TLB_TRANSLATE_FAULT:
	/* uncomment for part 3: */
	retval = mt_tlb_translate_fault(arg1);
        break;
      case MT_TLB_WRITE_FAULT:
	/* uncomment for part 3: */
	retval = mt_tlb_write_fault(arg1);
	break;
	
      default:
        printf("Invalid MT_OS system call number: %d",num);
        retval =  -1;
        break;
    }

    disable_interrupts(); /* re-entering mipsi */
    return retval;
}