PVS-Studio warning V547 for DeSmuME

static int _FAT_directory_lfnLength (const char* name) {
  ...
  for (i = 0; i < nameLength; i++) {
    if (name[i] < 0x20 || name[i] >= ABOVE_UCS_RANGE) {
      return -1;
    }
  }
  ...
}

This is what should have been written here: (unsigned char)(name[i]) >= ABOVE_UCS_RANGE

This suspicious code was found in DeSmuME project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression 'name[i] >= 0xF0' is always false. The value range of signed char type: [-128, 127]. DeSmuME_VS2005 directory.cpp 118

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