How to use FillChar to fill a 3D integer array (four bytes) in Delphi?

I know this works:

type _AAAB = array of array of array of byte;

procedure fillArray(var arr: _AAAB; const v: byte); overload;
var
  i, j, k: integer;
begin
  for i := 0 to High(arr) do
  begin
    for j := 0 to High(arr[i]) do
    begin
      FillChar(arr[i][j][0], Length(arr[i][j]), v); // sizeof(byte)=1
    end;
  end;
end;

However, if the array is type of integer, 4 byte, the above will not work as expected.. What i want to do here is to speed up the following:

type _AAAI = array of array of array of integer;

procedure fillArray(var arr: _AAAI; const v: integer); overload;
var
  i, j, k: integer;
begin
  for i := 0 to High(arr) do
  begin
    for j := 0 to High(arr[i]) do
    begin
      for k := 0 to High(arr[i][j]) do
      begin
        arr[i][j][k] := v;
      end;
    end;
  end;
end;

by replacing the inner loop... any advices? any faster method than FillChar? FillChar fills with byte, so it is not good here.

You can use a multibyte analogue to FillChar, such as FillWord or FillDWord. You might have to write those functions yourself, if your environment doesn't already include them.