public static byte[] longToBytes(long v) {
    byte[] p = new byte[8];
    for (int i = 0; i < 8; i++) {
        p[7-i] = (byte) ((v >>> 8*i) & 0xff);
        System.out.println("p="+ p[i]);
    }

    return p;
}

begin
  SetLength(p, 8);

  for i:= 0 to 7 do
    p[7-i] := byte( (v SHR (8 * i) ) and $ff );