FunCPU - Internal States and State Diagram

State	Encodedin binary	Explanation
init	0000	Initial, starting state. FunCPU remains in this state until it determines the lenght of the input expression
start	0001	Start phase is entered upon each reduction cycle. FunCPU decides if the expression is reduced, or the reduction process should continue.
copy	0010	In this state FunCPU copies one symbol after another from the source expression to the target.
inc	0011	Increment function is being executed.
dec	0100	Decrement function is being executed.
if-in	0101	if-then-else function is found. If the condition is constant, then the appropriate branch state is reached.
if-then	0110	Condition was true, the "then" part is selected.
if-skip-else	0111	Condition was true, the "else" part must be ignored.
if-else	1000	Condition was false, the "else" part must be selected.
if-skip-then	1001	Condition was false, the "then" part is ignored.
func-in	1010	User defined function entry. In this state the FunCPU checks, if all the arguments are available as constant, thus the function can be executed. Otherwise the function reduction is postponed.
func-copy	1011	FunCPU is unfolding the function definition and performing argument binding.
err-iin	1100	Some unexpected condition is encountered, most probably due to some hardware error or error in micro-program. Program execution is aborted.
err-arg	1101	Function with less argument is found, than expected. Program execution is aborted.
err-empty	1110	Empty expression or function definition is found. Program execution is aborted.
stop	1111	Input expression has been succesfully calculated. The processor will idle its final state and the result value is observable by looking at the data LEDs.