//---------------------------------------------------------------
// EXAMPLE EX13.C :  Demonstrate a FUNCTION call - III.
//                   Parameters passed TO/FROM function, add().
//
// C.P. Diduch, Dec 1999.
//---------------------------------------------------------------
#define	KEY_PA	0x138	  // 82C55A port addresses for PA,
#define KEY_PB	0x13A	  // PB,
#define KEY_PC	0x13C	  // PC and the
#define KEY_CON	0x13E	  // Control Register.

#include <conio.h> 	  // conio.h contains prototypes for 
			  // inportb() and outportb(). 
int add(int a, int b);	  // Function definition or prototype.
//---------------------------------------------------------------
void main()
{
int i, j, x;

outportb(KEY_CON, 0x82);  // Initialize 82C55A PPI with ports 
			  // KEY_PC and KEY_PA as OP ports and 
			  // port PB as an IP port.
i = 1;
j = 5;
x = add(i,j);
outportb(KEY_PC, x);
outportb(KEY_PA, j);
}
//---------------------------------------------------------------
int add(int a, int b) {
int j;
j = a + b;
return j;
}