<P> One method of dealing with the switching of unneeded components is called clock gating, which involves turning off the clock signal to unneeded components (effectively disabling them). However, this is often regarded as difficult to implement and therefore does not see common usage outside of very low - power designs . One notable recent CPU design that uses extensive clock gating is the IBM PowerPC - based Xenon used in the Xbox 360; that way, power requirements of the Xbox 360 are greatly reduced . Another method of addressing some of the problems with a global clock signal is the removal of the clock signal altogether . While removing the global clock signal makes the design process considerably more complex in many ways, asynchronous (or clockless) designs carry marked advantages in power consumption and heat dissipation in comparison with similar synchronous designs . While somewhat uncommon, entire asynchronous CPUs have been built without utilizing a global clock signal . Two notable examples of this are the ARM compliant AMULET and the MIPS R3000 compatible MiniMIPS . </P> <P> Rather than totally removing the clock signal, some CPU designs allow certain portions of the device to be asynchronous, such as using asynchronous ALUs in conjunction with superscalar pipelining to achieve some arithmetic performance gains . While it is not altogether clear whether totally asynchronous designs can perform at a comparable or better level than their synchronous counterparts, it is evident that they do at least excel in simpler math operations . This, combined with their excellent power consumption and heat dissipation properties, makes them very suitable for embedded computers . </P> <P> Every CPU represents numerical values in a specific way . For example, some early digital computers represented numbers as familiar decimal (base 10) numeral system values, and others have employed more unusual representations such as ternary (base three). Nearly all modern CPUs represent numbers in binary form, with each digit being represented by some two - valued physical quantity such as a "high" or "low" voltage . </P> <P> Related to numeric representation is the size and precision of integer numbers that a CPU can represent . In the case of a binary CPU, this is measured by the number of bits (significant digits of a binary encoded integer) that the CPU can process in one operation, which is commonly called word size, bit width, data path width, integer precision, or integer size . A CPU's integer size determines the range of integer values it can directly operate on . For example, an 8 - bit CPU can directly manipulate integers represented by eight bits, which have a range of 256 (2) discrete integer values . </P>

All the following are operations of the central processing unit except