duffy.c

#include <stdio.h>
#include <stdlib.h>

send(to, from, count)
register short *to, *from;
register count;
{
        register n = (count + 7) / 8;
        switch(count % 8) {
        case 0:      do {    *to = *from++;
        case 7:              *to = *from++;
        case 6:              *to = *from++;
        case 5:              *to = *from++;
        case 4:              *to = *from++;
        case 3:              *to = *from++;
        case 2:              *to = *from++;
        case 1:              *to = *from++;
                     } while(--n > 0);
        }
}


int main(int argc, char *argv[]) {

	int a = 10;
	int b = 0;

	send(&b,&a,1);

	printf("%d\n%d\n",a,b);
}