Intrinsic functions are functions built in to the compiler, usually to take advantage of specific CPU features that are inefficient to handle via external functions. The compiler's optimizer and code generator are fully integrated in with intrinsic functions, bringing to bear their full power on them. This can result in some surprising speedups.
btc(array, 35) = 0 array = [0]:x2, [1]:x108 btc(array, 35) = -1 array = [0]:x2, [1]:x100 bts(array, 35) = 0 array = [0]:x2, [1]:x108 btr(array, 35) = -1 array = [0]:x2, [1]:x100 bt(array, 1) = -1 array = [0]:x2, [1]:x100