internal Prl(Sprm sprm, byte[] operand)
 {
     this.sprm = sprm;
     this.operand = operand;
 }
 static int GetLengthFromSprm(Sprm sprm)
 {
     switch (sprm.spra)
     {
         case 0:
         case 1:
             return 1;
         case 2:
         case 4:
         case 5:
             return 2;
         case 3:
             return 4;
         case 6:
             return -1;
         case 7:
             return 3;
         default:
             throw new WordFileReaderException("Invalid Sprm.spra value");
     }
 }