age return and line feed to STDOUT
$e7e8	Serbrk	reads the status of STDIN and tests if it is E_SEMPTY
		If it is, carry is cleared, otherwise it is set.
$e7e5	Dezbout	writes a byte in decimal to STDOUT
$e7e2	Assign	handles a 10 byte table, that is e.g. used to implement
		the assign command in fsiec
		(carry=0): reads a table entry. parameter: table index in x,
		returns new value in x (a and y are preserved)
		(carry=1, x&lt;0): initialize table with a[i]=i
		(carry=1, 0&lt;=x&lt;10): write new table value