the Task data structure definition

task.h

#define TASK_STACK_SIZE 512

typedef enum {
  TS_RUNNABLE = 1, TS_BLOCKED = 2, TS_ZOMBIE = 3
} task_status_t;

typedef struct {
    jmp_buf       state;
    task_status_t status;
    unsigned char stack[TASK_STACK_SIZE];
} task_t;