/*
   =============================================================================
	mtquit.c -- Multi-Tasker -- shutdown
	Version 1 -- 1988-04-11 -- D.N. Lynx Crowe
	(c) Copyright 1988 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "stddefs.h"
#include "biosdefs.h"
#include "mtdefs.h"

extern	short		_MT_Nil();	/* system NIL task */

extern	TCB		*MT_CurP;	/* current TCB pointer */
extern	TCB		*MT_RdyQ;	/* ready queue pointer */

extern	unsigned	*_MT_Vc1;	/* old swapper TRAP vector 1 */
extern	unsigned	*_MT_Vc2;	/* old swapper TRAP vector 2 */

long			_MT_Stk[48];	/* a stack for _MT_Nil() */

TCB			_MT_TCB;	/* dummy TCB for shutdown */

/* 
*/

/*
   =============================================================================
	MTQuit() -- shut down the multi-tasker
   =============================================================================
*/

MTQuit()
{
	register short oldipl;

	oldipl = setipl(7);		/* DISABLE INTERRUPTS */

	BIOS(B_SETV, 40, _MT_Vc1);	/* restore old trap vector 1 */
	BIOS(B_SETV, 41, _MT_Vc2);	/* restore old trap vector 2 */

	_MT_Vc1 = (short *)NIL;		/* clear trap vector save area 1 */
	_MT_Vc2 = (short *)NIL;		/* clear trap vector save area 2 */

	/* setup dummy current TCB in case of 'accidents' */

	_MT_TCB.pri   = (unsigned)0xFFFF;	/* highest priority */
	_MT_TCB.slice = -1L;			/* no time slicing */

	MT_CurP = &_MT_TCB;		/* make dummy TCB current */
	MT_RdyQ = (TCB *)NIL;		/* clear the ready queue */

	setipl(oldipl);			/* RESTORE INTERRUPTS */
}