/*
 *  C64_x.h - Put the pieces together, X specific stuff
 *
 *  Frodo (C) 1994-1997,2002-2004 Christian Bauer
 *
 *  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
 */

#include "main.h"


static struct timeval tv_start;

#ifndef HAVE_USLEEP
/*
 *  NAME:
 *      usleep     -- This is the precision timer for Test Set
 *                    Automation. It uses the select(2) system
 *                    call to delay for the desired number of
 *                    micro-seconds. This call returns ZERO
 *                    (which is usually ignored) on successful
 *                    completion, -1 otherwise.
 *
 *  ALGORITHM:
 *      1) We range check the passed in microseconds and log a
 *         warning message if appropriate. We then return without
 *         delay, flagging an error.
 *      2) Load the Seconds and micro-seconds portion of the
 *         interval timer structure.
 *      3) Call select(2) with no file descriptors set, just the
 *         timer, this results in either delaying the proper
 *         ammount of time or being interupted early by a signal.
 *
 *  HISTORY:
 *      Added when the need for a subsecond timer was evident.
 *
 *  AUTHOR:
 *      Michael J. Dyer                   Telephone:   AT&T 414.647.4044
 *      General Electric Medical Systems        GE DialComm  8 *767.4044
 *      P.O. Box 414  Mail Stop 12-27         Sect'y   AT&T 414.647.4584
 *      Milwaukee, Wisconsin  USA 53201                      8 *767.4584
 *      internet:  mike@sherlock.med.ge.com     GEMS WIZARD e-mail: DYER
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <sys/time.h>
#include <sys/param.h>
#include <sys/types.h>

int usleep(unsigned long int microSeconds)
{
        unsigned int            Seconds, uSec;
        int                     nfds, readfds, writefds, exceptfds;
        struct  timeval         Timer;

        nfds = readfds = writefds = exceptfds = 0;

        if( (microSeconds == (unsigned long) 0)
                || microSeconds > (unsigned long) 4000000 )
        {
                errno = ERANGE;         /* value out of range */
                perror( "usleep time out of range ( 0 -> 4000000 ) " );
                return -1;
        }

        Seconds = microSeconds / (unsigned long) 1000000;
        uSec    = microSeconds % (unsigned long) 1000000;

        Timer.tv_sec            = Seconds;
        Timer.tv_usec           = uSec;

        if( select( nfds, &readfds, &writefds, &exceptfds, &Timer ) < 0 )
        {
                perror( "usleep (select) failed" );
                return -1;
        }

        return 0;
}
#endif

#ifdef __linux__
// select() timing is much more accurate under Linux
static void Delay_usec(unsigned long usec)
{
	int was_error;
	struct timeval tv;

	tv.tv_sec = 0;
	tv.tv_usec = usec;
	do {
		errno = 0;
		was_error = select(0, NULL, NULL, NULL, &tv);
	} while (was_error && (errno == EINTR));
}
#else
static void Delay_usec(unsigned long usec)
{
	usleep(usec);
}
#endif

/*
 *  Constructor, system-dependent things
 */

void C64::c64_ctor1(void)
{
	// Initialize joystick variables
	joy_minx[0] = joy_miny[0] = 32767;
	joy_maxx[0] = joy_maxy[0] = -32768;
	joy_minx[1] = joy_miny[1] = 32767;
	joy_maxx[1] = joy_maxy[1] = -32768;
}

void C64::c64_ctor2(void)
{
	gettimeofday(&tv_start, NULL);
}


/*
 *  Destructor, system-dependent things
 */

void C64::c64_dtor(void)
{
}


/*
 *  Start main emulation thread
 */

void C64::Run(void)
{
	// Reset chips
	TheCPU->Reset();
	TheSID->Reset();
	TheCIA1->Reset();
	TheCIA2->Reset();
	TheCPU1541->Reset();

	// Patch kernal IEC routines
	orig_kernal_1d84 = Kernal[0x1d84];
	orig_kernal_1d85 = Kernal[0x1d85];
	PatchKernal(ThePrefs.FastReset, ThePrefs.Emul1541Proc);

	quit_thyself = false;
	thread_func();
}


/*
 *  Vertical blank: Poll keyboard and joysticks, update window
 */

void C64::VBlank(bool draw_frame)
{
	// Poll keyboard
	TheDisplay->PollKeyboard(TheCIA1->KeyMatrix, TheCIA1->RevMatrix, &joykey);
	if (TheDisplay->quit_requested)
		quit_thyself = true;

	// Poll joysticks
	TheCIA1->Joystick1 = poll_joystick(0);
	TheCIA1->Joystick2 = poll_joystick(1);

	if (ThePrefs.JoystickSwap) {
		uint8 tmp = TheCIA1->Joystick1;
		TheCIA1->Joystick1 = TheCIA1->Joystick2;
		TheCIA1->Joystick2 = tmp;
	}

	// Joystick keyboard emulation
	if (TheDisplay->NumLock())
		TheCIA1->Joystick1 &= joykey;
	else
		TheCIA1->Joystick2 &= joykey;
       
	// Count TOD clocks
	TheCIA1->CountTOD();
	TheCIA2->CountTOD();

	// Update window if needed
	if (draw_frame) {
    	TheDisplay->Update();

		// Calculate time between VBlanks, display speedometer
		struct timeval tv;
		gettimeofday(&tv, NULL);
		if ((tv.tv_usec -= tv_start.tv_usec) < 0) {
			tv.tv_usec += 1000000;
			tv.tv_sec -= 1;
		}
		tv.tv_sec -= tv_start.tv_sec;
		double elapsed_time = (double)tv.tv_sec * 1000000 + tv.tv_usec;
		speed_index = 20000 / (elapsed_time + 1) * ThePrefs.SkipFrames * 100;

		// Limit speed to 100% if desired
		if ((speed_index > 100) && ThePrefs.LimitSpeed) {
			Delay_usec((unsigned long)(ThePrefs.SkipFrames * 20000 - elapsed_time));
			speed_index = 100;
		}

		gettimeofday(&tv_start, NULL);

		TheDisplay->Speedometer((int)speed_index);
	}
}


/*
 * The emulation's main loop
 */

void C64::thread_func(void)
{
	int linecnt = 0;

#ifdef FRODO_SC
	while (!quit_thyself) {

		// The order of calls is important here
		if (TheVIC->EmulateCycle())
			TheSID->EmulateLine();
		TheCIA1->CheckIRQs();
		TheCIA2->CheckIRQs();
		TheCIA1->EmulateCycle();
		TheCIA2->EmulateCycle();
		TheCPU->EmulateCycle();

		if (ThePrefs.Emul1541Proc) {
			TheCPU1541->CountVIATimers(1);
			if (!TheCPU1541->Idle)
				TheCPU1541->EmulateCycle();
		}
		CycleCounter++;
#else
	while (!quit_thyself) {

		// The order of calls is important here
		int cycles = TheVIC->EmulateLine();
		TheSID->EmulateLine();
#if !PRECISE_CIA_CYCLES
		TheCIA1->EmulateLine(ThePrefs.CIACycles);
		TheCIA2->EmulateLine(ThePrefs.CIACycles);
#endif

		if (ThePrefs.Emul1541Proc) {
			int cycles_1541 = ThePrefs.FloppyCycles;
			TheCPU1541->CountVIATimers(cycles_1541);

			if (!TheCPU1541->Idle) {
				// 1541 processor active, alternately execute
				//  6502 and 6510 instructions until both have
				//  used up their cycles
				while (cycles >= 0 || cycles_1541 >= 0)
					if (cycles > cycles_1541)
						cycles -= TheCPU->EmulateLine(1);
					else
						cycles_1541 -= TheCPU1541->EmulateLine(1);
			} else
				TheCPU->EmulateLine(cycles);
		} else
			// 1541 processor disabled, only emulate 6510
			TheCPU->EmulateLine(cycles);
#endif
		linecnt++;
#if !defined(__svgalib__)
		if ((linecnt & 0xfff) == 0 && gui) {

			// check for command from GUI process
		// fprintf(stderr,":");
			while (gui->probe()) {
				char c;
				if (gui->eread(&c, 1) != 1) {
					delete gui;
					gui = 0;
					fprintf(stderr,"Oops, GUI process died...\n");
				} else {
               // fprintf(stderr,"%c",c);
					switch (c) {
						case 'q':
							quit_thyself = true;
							break;
						case 'r':
							Reset();
							break;
						case 'p':{
							Prefs *np = Frodo::reload_prefs();
							NewPrefs(np);
							ThePrefs = *np;
							break;
						}
						default:
							break;
					}
				}
			}
		}
#endif
	}
}