Retro68/libretro/syscalls.c

/*
	Copyright 2015 Wolfgang Thaller.

	This file is part of Retro68.

	Retro68 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 3 of the License, or
	(at your option) any later version.

	Retro68 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.

	Under Section 7 of GPL version 3, you are granted additional
	permissions described in the GCC Runtime Library Exception, version
	3.1, as published by the Free Software Foundation.

	You should have received a copy of the GNU General Public License and
	a copy of the GCC Runtime Library Exception along with this program;
	see the files COPYING and COPYING.RUNTIME respectively.  If not, see
	<http://www.gnu.org/licenses/>.
*/

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/time.h>

#include <MacMemory.h>
#include <Processes.h>

int isatty(int fd) { return fd >= 0 && fd <= 2; }
void *sbrk(long increment)
{
	Debugger();
	return NewPtrClear(increment);
}

void _exit(int status)
{
	//if(status != 0)
	//	Debugger();
	ExitToShell();
	for(;;)
		;
}

ssize_t _consolewrite(int fd, const void *buf, size_t count);
ssize_t _consoleread(int fd, void *buf, size_t count);

ssize_t write(int fd, const void *buf, size_t count)
{
	return _consolewrite(fd,buf,count);
}

ssize_t read(int fd, void *buf, size_t count)
{
	return _consoleread(fd,buf,count);
}

int open(const char* name, int flags, mode_t mode)
{
	return -1;
}

int close(int fd)
{
	return -1;
}

int fstat(int fd, struct stat *buf)
{
	return -1;
}

off_t lseek(int fd, off_t offset, int whence)
{
	return (off_t) -1;
}

int kill(pid_t pid, int sig)
{
	if(pid == 42)
		_exit(42);
	else
		return -1;
}

pid_t getpid(void)
{
	return 42;
}

int gettimeofday(struct timeval *tp, void *__tz)
{
	/* Classic MacOS's GetDateTime function returns an integer.
	 * TickCount() has a slightly higher resolution, but is independend of the real-time clock.
	 */
	unsigned long secs;
	GetDateTime(&secs);
	unsigned long ticks = TickCount();

	static unsigned long savedTicks = 0, savedSecs = 0;
	
	if(!savedSecs)
	{
		savedTicks = ticks;
		savedSecs = secs;
	}
	else
	{
		unsigned long elapsedTicks = ticks - savedTicks;
		unsigned long elapsedSecs = secs - savedSecs;
		unsigned long expectedTicks = elapsedSecs * 60 + elapsedSecs * 3 / 20;
		
		if(expectedTicks > elapsedTicks)
			savedTicks = ticks;
		else
			savedTicks += expectedTicks;
		savedSecs = secs;
	}

	if(tp)
	{
		tp->tv_sec = secs - 86400 * (365 * 66 + 66/4);
		tp->tv_usec = (ticks - savedTicks) * 20000000 / 2003;
	}
}