/*
 * Copyright (c) 2021 joshua stein <jcs@jcs.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <setjmp.h>

#ifndef __UTHREAD_H__
#define __UTHREAD_H__

#define NUM_UTHREADS 6

enum {
	UTHREAD_STATE_DEAD,
	UTHREAD_STATE_SETUP,
	UTHREAD_STATE_RUNNING,
	UTHREAD_STATE_YIELDING,
	UTHREAD_STATE_SLEEPING,
	UTHREAD_STATE_REPEAT
};

enum {
	UTHREAD_SETJMP_DEFAULT,
	UTHREAD_SETJMP_YIELDED
};

struct uthread {
	short state;
	short id;
	jmp_buf env;
	void (*func)(struct uthread *, void *);
	void *arg;
	unsigned long sleeping_until;
	unsigned long stack_loc;
	unsigned long stack_gap;
};

extern struct uthread *uthread_current;
extern unsigned long uthread_ApplLimit;

void uthread_init(void);
struct uthread *uthread_add(void *func, void *arg);
void uthread_yield(void);
void uthread_coordinate(void);
void uthread_msleep(unsigned long millis);
void uthread_wakeup(struct uthread *uthread);
void uthread_verify(void);

#endif /* __UTHREAD_H__ */