Syntax:

gosub <label>
return

The GOSUB command calls a subroutine marked by a label. RETURN will pass control back to the caller. Nesting subroutines are supported (GOSUB and RETURN compiles to just plain JSR and RTS, nothing fancy). Stack overflow is not checked in runtime, but is quite unlikely to encounter. Example:

rem ** subroutines **
gosub first_routine
end

first_routine:
	print "hello world"
	gosub second_routine
	return
	
second_routine:
	print "and hello again"
	return

Note #1: make sure to use the END command before your routines if you don't want them to be executed in the normal program flow (like in the example above).

Note #2: there is no runtime call stack checking (e. g. no ?RETURN WITHOUT GOSUB ERROR). If your call stack is corrupted, the program is likely to break.

Note #3: Unlike procedures, subroutines do not open a new local scope.