Intrinsic Functions

Quick Reference

These functions are built into the compiler.

Elaboration Intrinsics

Function	Returns	Context	Purpose
width(expr)	int	comp/sim/formal	Returns the exact bit-width of any expression, wire, or register
is_signed(expr)	bool	comp/sim/formal	Returns true if the signal is a signed type
is_comptime(expr)	bool	comp/sim/formal	Returns true if the compiler knows the literal integer value of the expression

Simulation & Formal Intrinsics

These functions are used to control the hardware from sim blocks.

Function	Returns	Context	Purpose
assert(cond, msg)	void	sim/formal/comp	Prove condition always holds
assume(cond, msg)	void	sim/formal/comp	Assume condition holds (Precondition)
concat(expr, …)	inferred	sim/formal/comp	Concatenate multiple signals
cover(cond, msg)	void	sim/formal	Check if condition is reachable
cycle()	void	sim/formal	Advance 1 clock cycle
cycle(n)	void	sim/formal	Advance N clock cycles
reset()	void	sim	Hold reset for 1 cycle
reset(n)	void	sim	Hold reset for N cycles
poke(signal, value)	void	sim	Mutates the state of a simulator input from the testbench
print(msg, …)	void	sim	Debug output

Usage Notes

In Simulation: assert checks at runtime and fails the test if false. assume acts like an assert. In Formal: assert is a proof obligation. assume constrains the solver’s inputs. In Components: assert documents invariants that should always be true.