A microprocessor is a computer processor that incorporates the functions of the central processing unit (CPU) of a computer into a single integrated circuit (IC), or at most a few integrated circuits. The microprocessor is a digital, register-based and register-based integrated circuit that accepts input binary data, processes it according to instructions stored in its memory, and outputs output. Microprocessors contain combinational logic and sequential digital logic. The microprocessors operate on numbers and symbols represented in the binary number system.
Integrating an entire CPU into a single chip or into some chips greatly reduced the cost of processing power, increasing efficiency. Integrated circuit processors are produced in large quantities through highly automated processes, resulting in a low cost per unit. Single-chip processors increase reliability because there are far fewer electrical connections to fail. As microprocessor designs improve, the cost of manufacturing a chip (with smaller components built on a semiconductor chip of the same size) generally stays the same.
Prior to microprocessors, small computers had been built using circuit racks with many medium and small scale integrated circuits. The microprocessors combined this into one or a few large scale ICs. The continued increase in microprocessor capacity has meant that almost all computers are almost completely obsolete (see history of computer hardware), with one or more microprocessors used in everything from smaller embedded systems to larger mainframes and supercomputers .
The internal arrangement of a microprocessor varies depending on the age of the design and the intended purposes of the microprocessor. The complexity of an integrated circuit (IC) is limited by the physical limitations of the number of transistors that can be put on a chip, the number of packet terminations that can connect the processor to other parts of the system, the number of interconnections it is Possible to do on the chip, and the heat that the chip can dispel. Advancing technology makes the most complex and powerful chips feasible to manufacture.
A minimal hypothetical microprocessor could include only one arithmetic logic unit (ALU) and one logical control section. The ALU performs operations such as addition, subtraction, and operations such as AND or OR. Each ALU operation sets one or more indicators in a status register, which indicates the results of the last operation (zero value, negative number, overflow, or others). The control logic retrieves instruction codes from memory and initiates the sequence of operations required for the ALU to carry out the instruction. A single operation code can affect many individual data paths, registers, and other processor elements.
As the technology of integrated circuits advanced, it was feasible to manufacture processors more and more complex in a single chip. The size of the data objects became larger; By allowing more transistors on a chip to allow word size to increase from 4-bit and 8-bit words to today's 64-bit words. Added additional functions to the processor architecture; More records on chip accelerated programs, and complex instructions could be used to make programs more compact. Floating-point arithmetic, for example, was often not available on 8-bit microprocessors, but had to be carried out in software. Integrating the floating point unit first as a separate integrated circuit and then as part of the same microprocessor chip, accelerated floating point calculations.
Occasionally, the physical limitations of integrated circuits made these practices necessary. Instead of processing an entire long word in an integrated circuit, multiple circuits in subsets processed in parallel of each data word. While this required extra logic to handle, for example, carry and overflow within each segment, the result was a system that could handle, for example, 32-bit words using integrated circuits with a capacity of only four bits each.