task.h

// SYS86 project
// Task management

#pragma once

#include "config.h"
#include "types.h"

#define TASK_DOWN 0
#define TASK_RUN  1
#define TASK_WAIT 2

#define STACK_SIZE 256

// Offsets in task_s structure

#define task_stack 2*0
#define task_ssize 2*1
#define task_int   2*2
#define task_tsp   2*3
#define task_tss   2*4
#define task_usp   2*5
#define task_uss   2*6

#ifndef _ASSEMBLY

// Forward declaration

struct task_s;

// Wait event structure
// Very simplified wait queue :-)

struct wait_s
	{
	struct task_s * t;  // task to wake up
	};

// Task structure

struct task_s
	{
	// Shared with assembly

	word_t * stack;  // 0
	word_t ssize;    // 1
	word_t inter;    // 2
	reg_t top_sp;    // 3
	seg_t top_ss;    // 4
	reg_t user_sp;   // 5
	seg_t user_ss;   // 6

	// C only

	int stat;
	};

#define TASK_MAX 5

extern struct task_s * tasks [TASK_MAX];

#define TASK_NUM_SERIAL 3

extern struct task_s * task_prev;
extern struct task_s * task_now;
extern struct task_s * task_next;

// From assembly

void stack_init_near (struct task_s *, void * entry, word_t * stack);
void stack_init_far (struct task_s *, word_t ip, word_t cs, word_t sp, word_t ss);

void task_switch (void);

// From C code

void task_init_near (int i, struct task_s * t, void * entry, word_t size);
void task_init_far (int i, struct task_s * t, word_t seg, word_t size);

void task_lock (void);
void task_unlock (void);

void task_sched (void);

typedef int (* cond_f) (void * object);
void task_wait (struct wait_s * wait, cond_f test, void * param, int single);
void task_event (struct wait_s * wait);

void task_init (void);

#endif // !_ASSEMBLY