private static RegisterSpecList explicitize(RegisterSpecList orig) {
    int wordCount = wordCount(orig);
    int sz = orig.size();

    if (wordCount == sz) {
      return orig;
    }

    RegisterSpecList result = new RegisterSpecList(wordCount);
    int wordAt = 0;

    for (int i = 0; i < sz; i++) {
      RegisterSpec one = orig.get(i);
      result.set(wordAt, one);
      if (one.getCategory() == 2) {
        result.set(wordAt + 1, RegisterSpec.make(one.getReg() + 1, Type.VOID));
        wordAt += 2;
      } else {
        wordAt++;
      }
    }

    result.setImmutable();
    return result;
  }
Returns a register list which is equivalent to the given one, except that it splits category-2
registers into two explicit entries. This returns the original list if no modification is
required

@param orig {@code non-null;} the original list
@return {@code non-null;} the list with the described transformation
android/android_framework/dex-maker/src/main/java/com/android/dx/dex/code/form/Form35c.java