Minix1.1/usr/src/kernel/proc.h

/* Here is the declaration of the process table.  Three assembly code routines
 * reference fields in it.  They are restart(), save(), and csv().  When 
 * changing 'proc', be sure to change the field offsets built into the code.
 * It contains the process' registers, memory map, accounting, and message
 * send/receive information.
 */

EXTERN struct proc {
  int p_reg[NR_REGS];		/* process' registers */
  int *p_sp;			/* stack pointer */
  struct pc_psw p_pcpsw;		/* pc and psw as pushed by interrupt */
  int p_flags;			/* P_SLOT_FREE, SENDING, RECEIVING, etc. */
  struct mem_map p_map[NR_SEGS];/* memory map */
  int *p_splimit;		/* lowest legal stack value */
  int p_pid;			/* process id passed in from MM */

  real_time user_time;		/* user time in ticks */
  real_time sys_time;		/* sys time in ticks */
  real_time child_utime;	/* cumulative user time of children */
  real_time child_stime;	/* cumulative sys time of children */
  real_time p_alarm;		/* time of next alarm in ticks, or 0 */

  struct proc *p_callerq;	/* head of list of procs wishing to send */
  struct proc *p_sendlink;	/* link to next proc wishing to send */
  message *p_messbuf;		/* pointer to message buffer */
  int p_getfrom;		/* from whom does process want to receive? */

  struct proc *p_nextready;	/* pointer to next ready process */
  int p_pending;		/* bit map for pending signals 1-16 */
} proc[NR_TASKS+NR_PROCS];

/* Bits for p_flags in proc[].  A process is runnable iff p_flags == 0 */
#define P_SLOT_FREE      001	/* set when slot is not in use */
#define NO_MAP           002	/* keeps unmapped forked child from running */
#define SENDING          004	/* set when process blocked trying to send */
#define RECEIVING        010	/* set when process blocked trying to recv */

#define proc_addr(n) &proc[NR_TASKS + n]
#define NIL_PROC (struct proc *) 0

EXTERN struct proc *proc_ptr;	/* &proc[cur_proc] */
EXTERN struct proc *bill_ptr;	/* ptr to process to bill for clock ticks */
EXTERN struct proc *rdy_head[NQ];	/* pointers to ready list headers */
EXTERN struct proc *rdy_tail[NQ];	/* pointers to ready list tails */

EXTERN unsigned busy_map;		/* bit map of busy tasks */
EXTERN message *task_mess[NR_TASKS+1];	/* ptrs to messages for busy tasks */