◄Summary► ◄Timings► ──────────────────────────────────────────────────────────────────────────── Partial Arctangent Syntax: FPATAN Finds the partial tangent by calculating Z = ARCTAN(Y / X). X is taken from ST and Y from ST(1). On the 8087 and 80287, Y and X must be in the range 0 ≤ Y < X < ∞. On the 80387, there is no restriction on X and Y. X is popped from the stack and Z replaces Y in ST. -♦-