switch(len) {
	case 11: c+=((unsigned int)k[10]<<24);
	case 10: c+=((unsigned int)k[9]<<16);
	case 9 : c+=((unsigned int)k[8]<<8);
	case 8 : b+=((unsigned int)k[7]<<24);
	case 7 : b+=((unsigned int)k[6]<<16);
	case 6 : b+=((unsigned int)k[5]<<8);
	case 5 : b+=k[4];
	case 4 : a+=((unsigned int)k[3]<<24);
	case 3 : a+=((unsigned int)k[2]<<16);
	case 2 : a+=((unsigned int)k[1]<<8);
	case 1 : a+=k[0];
     /* case 0: nothing left to add */
}