CPU design

Processor design is the design engineering task of creating a microprocessor, a component of computer hardware. It is a subfield of electronics engineering and computer engineering. The design process involves choosing an instruction set and a certain execution paradigm (e.g. VLIW or RISC) and results in a microarchitecture described in e.g. VHDL or Verilog. This description is then manufactured employing some of the various semiconductor device fabrication processes. This results in a die which is bonded onto a chip carrier. This chip carrier is then soldered onto, or inserted into a socket on, a printed circuit board (PCB).

The mode of operation of any microprocessor is the execution of lists of instructions. Instructions typically include those to compute or manipulate data values using registers, change or retrieve values in read/write memory, perform relational tests between data values and to control program flow.

CPU design focuses on six main areas:

CPUs designed for high-performance markets might require custom designs for each of these items to achieve frequency, power-dissipation, and chip-area goals whereas CPUs designed for lower performance markets might lessen the implementation burden by acquiring some of these items by purchasing them as intellectual property. Control logic implementation techniques (logic synthesis using CAD tools) can be used to implement datapaths, register files, and clocks. Common logic styles used in CPU design include unstructured random logic, finite-state machines, microprogramming (common from 1965 to 1985), and Programmable logic arrays (common in the 1980s, no longer common).

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