#include <stdio.h>

/* MONITOR THE BITS ON THE 8255 I/O BOARD AT SPECIFIED PORT ADDRESS
 *    erco 05/29/00 - (yes, memorial day weekend)
 */

/* WRITE STRING TO VIDEO MEMORY
 * Supply Y position, array of characters, array of attributes for each
 * char, and 'overwrite' to end of line flag. Used exclusivly by RUNBAR().
 */
void bar(int, int, char *);
void bar(x,y, string)
    int x,y;		/* y location on screen */
    char *string;	/* the string to put on screen */
{
    register t;
    static char
        *mono,			/* MUST BE LARGE MODEL */
	*cga;			/* MUST BE LARGE MODEL */

    mono = (char *)(0xb0000000 + (y-1)*160+(x*2));
    cga  = (char *)(0xb8000000 + (y-1)*160+(x*2));

    for (t=0; string[t]; t++)
    {
        *mono = string[t]; mono += 2;
	*cga  = string[t]; cga  += 2;
    }
}

/* SCROLL LINE RIGHT STARTING AT x,y */
void scrollright(x,y)
{
    register t;
    static char
        *mono,			/* MUST BE LARGE MODEL */
	*cga;			/* MUST BE LARGE MODEL */

    mono = (char *)(0xb0000000 + (y-1)*160+(78*2));
    cga  = (char *)(0xb8000000 + (y-1)*160+(78*2));

    for ( ; x < 79; x++ )
    {
        *(mono+2) = *mono; mono--; *(mono+2) = *mono; mono--;
        *(cga+2)  = *cga;  cga--;  *(cga+2)  = *cga;  cga--;
    }
}

void InitScreen(port)
{
    int position = 1, t, bitcount, val;

    printf("\033[2J\033[1H\r     Pin Port   Mask   State", port);

    for ( t=0; t<3; port++, t++ )
    {
        int bitmask = 1;
	for ( bitcount=0; bitcount<8; bitcount++ )
	{
	    ++position;
	    printf("\033[%d;1H\033[0m\r", position);

	    /* HANDLE PRINTING VERTICAL BRACKETS */
	    switch ( bitcount )
	    {
	        case 0:  printf("  %c%c ", 0xda, 0xc4); break;
	        case 4:  printf("%c %c  ", 'A'+t, 0xb3); break;
		default: printf("  %c  ", 0xb3); break;
	        case 7:  printf("  %c%c ", 0xc0, 0xc4); break;
	    }

	    printf("%s%02d  0x%04x 0x%02x - ",
		   ( bitmask == 1 ) ? "\033[1m" : "\033[0m",
		   00,
		   port,
		   bitmask);
	    bitmask <<= 1;
	}
    }
}

int main(argc, argv)
    int argc;
    char **argv;
{
    int cursor_pos = 1;		/* 1 thru 24 */
    int portbase = 0x0300;	/* whatever the 8255 port address is */
    char s[80];

    /* PARSE COMMAND LINE */
    if ( argc >= 2 )
    {
	if ( argv[1][0] == '-' || 
	     sscanf(argv[1], "%x", &portbase) != 1 )
	{
	    fprintf(stderr,"8255 - monitor 3 ports on an 8255 I/O board\n");
	    fprintf(stderr,"Greg Ercolano 05/29/00. Public domain software.\n");
	    fprintf(stderr,"\n");
	    fprintf(stderr,"  usage: 8255 [port base in hex]\n");
	    fprintf(stderr,"example: 8255 0300   # monitor ports 0x300-302\n");
	    fprintf(stderr,"\n");
	    fprintf(stderr,"If unspecified, default port base is 0x300\n");
	    exit(1);
	}
    }

    /* SETUP INITIAL SCREEN LAYOUT */
    InitScreen(portbase);

    /* UPDATE LOOP */
    while ( 1 )
    {
	int port,
	    y = 2,
	    x = 23;
	for ( port = portbase; port < portbase+3; port++ )
	{
	    int byte = inp(port),
	        bitmask = 1,
	        bitcount;
	    for ( bitcount = 0; bitcount<8; bitcount++ , bitmask <<= 1, y++)
	    {
	        sprintf(s, "%s %c", 
		    ((byte & bitmask) ? "SET" : "clr"),
		    ((byte & bitmask) ? '-' : '_'));
		scrollright(26, y);
	        bar(x, y, s);
	    }
	}

	if ( kbhit() ) break;
    }
}