A processor core comprising in its set of instructions, a combined addition and bound-checking instruction (ADDCK) defining an integer n implicitly, or explicitly as a parameter of the instruction; an adder having a width p strictly greater than n bits; and a processing circuit (MUX, 42) designed to respond to the combined instruction by activating an overflow signal (BX) when the adder generates a carry of rank n during the addition of operands of width p.