microprocessor

microprocessor
Name	microprocessor

microprocessor. A microprocessor is a single integrated circuit that contains the core functions of a central processing unit. It is the fundamental building block of modern digital computers and countless embedded systems. By integrating the arithmetic logic unit, control unit, and register file onto one semiconductor device, it enabled the microcomputer revolution of the 1970s and 1980s. Its invention is widely credited to engineers at Intel Corporation with the introduction of the Intel 4004.

History

The development of the microprocessor was a convergence of advancements in semiconductor device fabrication and computer architecture. Early electronic computers like the ENIAC used discrete components, but the invention of the integrated circuit by Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor paved the way for greater complexity. The first commercially available device was the 4-bit Intel 4004, designed by Federico Faggin, Ted Hoff, and Stanley Mazor for a Busicom calculator. This was quickly followed by the 8-bit Intel 8008 and the seminal Intel 8080, which became the heart of early Altair 8800 machines. The MOS Technology 6502 and Zilog Z80 fueled the home computer boom, powering systems like the Apple II and Commodore 64. The IBM Personal Computer adopted the Intel 8088, cementing the dominance of the x86 architecture. Parallel developments included bit-slice designs and the rise of reduced instruction set computing architectures like ARM architecture and MIPS architecture.

Design and implementation

The design process begins with defining an instruction set architecture, which specifies the operations the device can perform. This architecture is then realized through microarchitecture, which defines the internal organization, including elements like the pipeline (computing), cache memory, and superscalar execution units. Designers use hardware description languages like Verilog and VHDL for logic synthesis. The physical layout is created using electronic design automation tools, culminating in a photomask set for semiconductor fabrication. This fabrication occurs in semiconductor fabrication plants using processes like photolithography and chemical-mechanical planarization on silicon wafers. Key design considerations include power consumption, heat dissipation, clock signal distribution, and signal integrity.

Operation

Fundamental operation follows the instruction cycle, typically consisting of fetch (computing), instruction decode, execute, and writeback stages. The control unit generates signals that coordinate the movement of data between the arithmetic logic unit, processor registers, and system buses like the front-side bus. Instructions are fetched from main memory via the memory management unit, which may also handle virtual memory translation. The arithmetic logic unit performs mathematical and logical operations. Interrupt (computing) signals from peripherals can alter the normal flow, causing the processor to execute an interrupt handler. Modern devices use techniques like branch prediction and out-of-order execution to improve efficiency.

Performance and capabilities

Performance is traditionally measured in instructions per second or FLOPS, though benchmarks like SPECint are more comprehensive. Key architectural factors include clock rate, instructions per cycle, memory hierarchy efficiency, and parallel computing capabilities. The transition from 32-bit computing to 64-bit computing expanded the address space and data width. The end of Dennard scaling led to a focus on multi-core processors, where performance gains come from thread (computing)-level parallelism. Features like simultaneous multithreading, advanced vector extensions, and integrated graphics processing units have expanded capabilities. Thermal design power is a critical constraint for performance in mobile devices and data centers.

Types and applications

Microprocessors are categorized by their intended application domain. General-purpose computing on personal computers and server (computing)s is dominated by x86 designs from Intel and Advanced Micro Devices. Embedded systems and mobile devices overwhelmingly use ARM architecture-based system on a chip designs, such as those from Qualcomm and Apple Inc.. Microcontrollers, which integrate memory and input/output peripherals, are ubiquitous in automotive electronics, industrial control systems, and consumer electronics. Other types include digital signal processors for real-time signal processing, graphics processing units for parallel workloads, and field-programmable gate arrays for reconfigurable logic.

Market and manufacturers

The global market is characterized by distinct segments. The high-performance segment for data centers and personal computers is a duopoly between Intel Corporation and Advanced Micro Devices. The vast mobile device and embedded market is led by ARM Holdings, which licenses its designs to fabless firms like Qualcomm, MediaTek, and Apple Inc., which are manufactured by foundry (electronics) companies like Taiwan Semiconductor Manufacturing Company and Samsung Electronics. Other significant players include IBM with its POWER Architecture, and Nvidia in accelerated computing. The market is heavily influenced by geopolitical factors, export controls, and massive investments in semiconductor fabrication plant construction, particularly in the United States, Taiwan, and South Korea.

Category:Microprocessors Category:Computer hardware Category:Digital electronics