type SmallInt = ShortInt;
SmallInt is a signed integer type which is not larger than Integer. On some platforms it is 16 bits wide and thus has a range of -32768 .. 32767. It is the same as ShortInt (see ShortInt).
There are lots of other integer types in GPC, see Integer Types.
SmallInt is a Borland Delphi 2.0 extension.
program SmallIntDemo; var a: SmallInt; begin a := 42; WriteLn (a) end.
ShortInt, Integer Types, Subrange Types.