//---------------------------------------------------------------
// EXAMPLE EX16.C :  Demonstrate a FUNCTION call - V.
//
// Using a POINTER to pass an array to/from a function. 
//
// 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(). 

char sum(char *A, char N); // Function definition or prototype.
//---------------------------------------------------------------
void main()
{
unsigned char DATA[] = {0,1,2,3,4,5,6,7};
char Y;

outportb(KEY_CON, 0x82);   // Initialize 82C55A PPI with ports 
			   // KEY_PC and KEY_PA as OP ports and 
			   // port PB as an IP port.
Y = sum(&DATA[0], 5);
outportb(KEY_PC, Y);
Y = sum(&DATA[0], 7);
outportb(KEY_PC, Y);
}
//---------------------------------------------------------------
char sum(char *A, char N) {
unsigned i, j;
char X;

j = 0;
X = 0;
for (i = 0; i < N; i++) {
   X = X + *(A + j);
   j = j + 1;
   }
return X;
}