Javascript AGC assembly code simulator about apollo-11 HOT 3 CLOSED

            // Allowed registers: A, B, C, D, SP
            var parseRegister = function (input) {
                input = input.toUpperCase();

                if (input === 'A') {
                    return 0;
                } else if (input === 'B') {
                    return 1;
                } else if (input === 'C') {
                    return 2;
                } else if (input === 'D') {
                    return 3;
                } else if (input === 'SP') {
                    return 4;
                } else {
                    return undefined;
                }
          };