/* toggle parallel port bit wait for cr */

#include <std.h>

FIO stdout;

main()

{
	int a;

	out(0x4f,0);		/* select group 0 */
	out(0x4a,0xc0);		/* enable printer */
	for( ; ; )	/* endless loop */
	{
		a=quest();	/* question operator */

		if(a < 17)	/* is a less than 17 */
			outit(a);	/* output to right port */
		else
			break;
	}

}

outit(a)
	int a;
{
	int b;

	if(a < 9)	/* is it in the first port */
	{
		b = 1;		/* set up b for output */
		b <<= (a - 1);
		for( ; ; )	/* endless loop */
		{
			out(0x48,b);	/* output to second port */
			out(0x48,0);	/* output 0 to port */
			if(cpm(11) != 0)	/* cp/m status */
			{
				cpm(1);	/* get useless char */
				break;
			}
		}
	}
	else 		/* is it in the second port */
	{
		b = 1;		/* set up b for output */
		b <<= (a - 9);
		for( ; ; )	/* endless loop */
		{
			out(0x49,b);	/* output to second port */
			out(0x49,0);	/* output 0 to port */
			if(cpm(11) != 0)	/* cp/m status */
			{
				cpm(1);	/* get useless char */
				break;
			}
		}
	}
}

quest()		/* question operator */

{
	int a;

	putfmt("\ntype in a number for the bit you want on.\n");
	putfmt("type any key to end that bit loop\n");
	putfmt("type in any number over 16 to end test\n");
	getfmt("%i",&a);
	return(a);
}