floating-point hardware including a square root function, a number of loop instructions and index registers to support them, and used a complex three-address instruction format. The three-address system meant that every instruction included the address of up to two operands and the result. The system did not include an accumulator, the results of all operations being written back to main memory. This was desirable at the time, when computer memories were generally comparable in speed to the processors (today memory is much slower than processors).