ase 0xD: /* OUT */ this.write(this.memory.slice(this.i, this.i+z), x, y); break;
          case 0xE:
            switch(x) {
              case 0x0: /* SKP */ if (this.key == n) { this.pc += 2 } break;
              case 0x1: /* SKN */ if (this.key != n) { this.pc += 2 } break;
              default: unknown(instr); break;
            }
          break;
          case 0xF:
            switch(z) {
              case 0x0: /* LDK */ this.waitKey = x; break;
              case 0x1: /* MEA */ r = this.i + this.v