kernel_data.h

// kernel_data.h, 159
// kernel data are all declared in kernel.c during bootstrap
// kernel.c code referance them as 'extern'

#ifndef _KERNEL_DATA_H_       // 'name-mangling' prevention
#define _KERNEL_DATA_H_       // 'name-mangling' prevention

#include "kernel_types.h"     // defines pid_q_t, pcb_t, PROC_NUM, PROC_STACK_SIZE

extern int run_pid;         // PID of current selected process to run, 0 means none
extern int current_time;
extern pid_q_t avail_pid_q, ready_pid_q;   // not used and ready PID's
extern pcb_t pcb[PROC_NUM];           // Process Control Blocks
extern char proc_stack[PROC_NUM][PROC_STACK_SIZE]; // process runtime stacks
extern semaphore_t video_sem;

#endif