How to use the @glimmer/program.PrimitiveType.NEGATIVE function in @glimmer/program

function decodeSmi(smi: number): number {
  switch (smi & 0b111) {
    case PrimitiveType.NUMBER:
      return smi >> 3;
    case PrimitiveType.NEGATIVE:
      return -(smi >> 3);
    default:
      throw unreachable();
  }
}

let value = primitive >> 3;

    switch (flag) {
      case PrimitiveType.NUMBER:
        stack.push(value);
        break;
      case PrimitiveType.FLOAT:
        stack.push(vm[CONSTANTS].getNumber(value));
        break;
      case PrimitiveType.STRING:
        stack.push(vm[CONSTANTS].getString(value));
        break;
      case PrimitiveType.BOOLEAN_OR_VOID:
        stack.pushEncodedImmediate(primitive);
        break;
      case PrimitiveType.NEGATIVE:
        stack.push(vm[CONSTANTS].getNumber(value));
        break;
      case PrimitiveType.BIG_NUM:
        stack.push(vm[CONSTANTS].getNumber(value));
        break;
    }
  },
  OpcodeKind.Mut

function encodeSmi(primitive: number) {
  if (primitive < 0) {
    return Math.abs(primitive) << 3 | PrimitiveType.NEGATIVE;
  } else {
    return primitive << 3 | PrimitiveType.NUMBER;
  }
}