a bss machine m is given by a list formula_1of formula_2 instructions (to be described below), indexed formula_3. a configuration of m is a tuple formula_4, where "k" is the index of the instruction to be executed next, "r" and "w" are copy registers holding non-negative integers, and formula_5 is a list of real numbers, with all but finitely many being zero. the list formula_6 is thought of as holding the contents of all registers of m. the computation begins with configuration formula_7 and ends whenever formula_8; the final content of "x" is said to be the output of the machine.