/*
   =============================================================================
	mtdefs.h -- mutlitasker definitions
	Version 22 -- 1988-04-14 -- D.N. Lynx Crowe
	(c) Copyright 1988 -- D.N. Lynx Crowe
	WARNING:  all of these data structures are highly ORDER DEPENDENT.
   =============================================================================
*/

/* #define	DEBUGGER	define to enable debugging in all MT code */

#define	MT_NilSR	(unsigned)0x2200	/* SR value for _MT_Nil() */
#define	MT_DfPri	(unsigned)0x4000	/* default task priority */

#define	MTF_RDY		0x0001		/* task ready to run  (on MT_RdyQ) */
#define	MTF_SWT		0x0002		/* task waiting on a semaphore */
#define	MTF_RUN		0x0004		/* task running (MT_CurP) */
#define	MTF_STP		0x0008		/* task to be stopped  (waiting) */

#define	MTF_OCC		0x8000		/* TCB occupied */

/* 
*/

typedef	long	SEM;			/* Semaphore */

typedef	struct	_mt_msg	{		/* Message */

	struct	_mt_msg	*next;		/* pointer to next message in queue */
	SEM	reply;			/* reply semaphore */
	long	msize;			/* message size */
	long	mdata;			/* message data or pointer */
} MSG;

typedef	struct	_mt_mbx	{		/* Mailbox */

	SEM	mail;			/* mail waiting semaphore */
	SEM	mutex;			/* mutual exclusion semphore */
	MSG	*head;			/* pointer to head of message queue */
	MSG	*tail;			/* pointer to tail of message queue */
} MBOX;

typedef	struct	_mt_tcb	{		/* Task Control Block */

	struct	_mt_tcb	*next;		/* pointer to next TCB in queue */
	struct	_mt_tcb *fwd;		/* pointer to next TCB in chain */
	unsigned	tid;		/* task identifier */
	unsigned	pri;		/* task priority */
	long		slice;		/* time slice */
	long		reg[16];	/* registers */
	long		sp;		/* stack pointer */
	long		pc;		/* program counter */
	unsigned	sr;		/* status register */
	unsigned	flags;		/* task status flags */
	long		tos;		/* pointer to top of stack */
} TCB;

struct	_mt_str {			/* Multi-Tasker variable structure */

	TCB		*TCBs;		/* TCB chain pointer */
	TCB		*CurP;		/* current TCB pointer */
	TCB		*RdyQ;		/* ready queue pointer */
	unsigned	IDct;		/* TCB ID counter */
};

struct	_mt_def	{			/* Multi-Tasker interface block */

	struct _mt_str	*mtp;	/* pointer to mt_str structure */
	SEM	*FCLK;		/* pointer to SemFCLK */
	SEM	*Quit;		/* pointer to SemQuit */
	MBOX	*Vid;		/* pointer to MSG_Vid */
};