VARCem/src/timer.h

/*
 * VARCem	Virtual ARchaeological Computer EMulator.
 *		An emulator of (mostly) x86-based PC systems and devices,
 *		using the ISA,EISA,VLB,MCA  and PCI system buses, roughly
 *		spanning the era between 1981 and 1995.
 *
 *		This file is part of the VARCem Project.
 *
 *		Definitions for the system timer module.
 *
 * Version:	@(#)timer.h	1.0.2	2018/05/04
 *
 * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
 *		Miran Grca, <mgrca8@gmail.com>
 *		Sarah Walker, <tommowalker@tommowalker.co.uk>
 *
 *		Copyright 2017,2018 Fred N. van Kempen.
 *		Copyright 2016-2018 Miran Grca.
 *		Copyright 2008-2018 Sarah Walker.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free  Software  Foundation; either  version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is  distributed in the hope that it will be useful, but
 * WITHOUT   ANY  WARRANTY;  without  even   the  implied  warranty  of
 * MERCHANTABILITY  or FITNESS  FOR A PARTICULAR  PURPOSE. See  the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the:
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place - Suite 330
 *   Boston, MA 02111-1307
 *   USA.
 */
#ifndef EMU_TIMER_H
# define EMU_TIMER_H


extern int64_t timer_start;

#define timer_start_period(cycles)                      \
        timer_start = cycles;

#define timer_end_period(cycles) 			\
	do 						\
	{						\
                int64_t __diff = timer_start - (cycles);      \
		timer_count -= __diff;			\
                timer_start = cycles;                   \
		if (timer_count <= 0)			\
		{					\
			timer_process();		\
			timer_update_outstanding();	\
		}					\
	} while (0)

#define timer_clock()                                                   \
	do 						                \
	{						                \
                int64_t __diff;                                         \
                if (AT)                                                 \
                {                                                       \
                        __diff = timer_start - (cycles << TIMER_SHIFT); \
                        timer_start = cycles << TIMER_SHIFT;            \
                }                                                       \
                else                                                    \
                {                                                       \
                        __diff = timer_start - (cycles * xt_cpu_multi); \
                        timer_start = cycles * xt_cpu_multi;            \
                }                                                       \
		timer_count -= __diff;			                \
		timer_process();		                        \
        	timer_update_outstanding();	                        \
	} while (0)

extern void timer_process(void);
extern void timer_update_outstanding(void);
extern void timer_reset(void);
extern int64_t timer_add(void (*callback)(void *priv), int64_t *count, int64_t *enable, void *priv);
extern void timer_set_callback(int64_t timer, void (*callback)(void *priv));

#define TIMER_ALWAYS_ENABLED &timer_one

extern int64_t timer_count;
extern int64_t timer_one;

#define TIMER_SHIFT 6

extern int64_t TIMER_USEC;


#endif	/*EMU_TIMER_H*/