bcd method
Implementation
void bcd(int opcode) {
memory[registers.index] = registers.v[_rxIndex(opcode)] ~/ 100;
memory[registers.index + 1] = (registers.v[_rxIndex(opcode)] ~/ 10) % 10;
memory[registers.index + 2] = registers.v[_rxIndex(opcode)] % 10;
}