For example, a branch might be taken only if the result of a previous subtraction produced a negative result. Data that are tested for conditional branching are stored in special locations in the CPU called flags. The CPU is driven by one or more repetitive clock circuits that send a constant stream of pulses throughout the CPU's circuitry. The CPU uses these clock pulses to synchronize its operations. The smallest increments of CPU work are completed between sequential clock pulses.
More complex tasks take several clock periods to complete.
Clock pulses are measured in Hertz, or number of pulses per second. Clock pulses are a measure of the speed of a processor. Fixed-point numbers have a specific number of digits on either side of the decimal point. This restriction limits the range of values that are possible for these numbers, but it also allows for the fastest arithmetic. Floating-point numbers are numbers that are expressed in scientific notation, in which a number is represented as a decimal number multiplied by a power of ten.