Wikipedia claims that TP 6 added inline assembly, I looked at the TP 4 manual and found you can write

  procedure FillWord(var Dest,Count,Data: word);
  begin
  inline(
     $C4/$BE/Dest/       { LES DI,Dest[BP] }
     $8B/$8E/Count/      { MOV CX,Count[BP] }
     $8B/$86/Data/       { MOV AX,Data[BP] }
     $FC/                { CLD }
     $F3/$AB);           { REP STOSW }
  end;

Note that {} is a comment so this is raw machine code expressed in bytes where you can substitute in addresses or other values. Not as cool as what came later.