Remarks 

The {$HIGHCHARUNICODE ON} directive controls the behavior of characters #$80 ... #$FF. 

When HIGHCHARUNICODE is OFF:

• All #$xx 2-digit literals are parsed as AnsiChar.
• All #$xxxx 4-digit literals are parsed as WideChar.

• All #$xx 2-digit and #$xxxx 4-digit literals are parsed as WideChar.

 var
      A: AnsiChar;
      W: WideChar;
begin

     {$HIGHCHARUNICODE OFF}
     A := #$80; // A is $80
     W := #$80; // W is $20AC

    {$HIGHCHARUNICODE ON}
     A := #$80; // A is converted to '?' ($3F) after narrowing it down from WideChar to AnsiChar
     W := #$80; // W is $80

end;