As a processor core or arithmetic core ( English core ) of the central part of a is the arithmetic unit or a microprocessor , respectively. Many modern processors have multiple cores (see multi-core processor ).
A processor core consists of at least:
- an arithmetic-logic unit (ALU, circuit blocks for logic and integer operations)
- register the rake ( accumulator and mostly others)
- the essential parts of the control unit
- Address decoder (management and, if necessary, further counting of memory addresses as well as loading and saving of values from memory addresses in registers or vice versa)
- Instruction decoder (interconnection of registers as inputs and outputs with function blocks of the ALU in order to carry out the current command).
Optional components are:
- Interrupt decoder
- Floating point unit
- Memory Management Unit (MMU)
- other mechanisms that are closely related to the internal architecture of the processor .
In general, the following are considered as not belonging to the processor core, even if they are on the same chip :
- Read-only memory (ROM)
- Working memory (RAM)
- Peripheral groups, e.g. B.
A processor core is a real implementation of a processor architecture . Each architecture has its own set of instructions and requires a compiler suitable for it to create programs. Different types of processors with largely the same core design are referred to as a "family". If a processor design is significantly revised or changed, a new “family” is created that is almost always downward compatible . If downward compatibility is abandoned, one speaks i. A. from a new / different processor architecture.
In chip development, the processor core is used as a module that can be combined with other modules to form a complete processor. Sometimes the processor core can be configured differently, e.g. B. with more or fewer registers, with or without floating point unit and the like. This creates different derivatives that all belong to the same architecture family (example: the ARM architecture is offered in a highly configurable way.) By separating the processor core, memory / cache and (processor) peripherals, microprocessor manufacturers can offer variants that contain peripherals arranged differently around the same core or are equipped with more or fewer (on-chip) RAM / ROM memories. Peripherals of the processor core include, for example, on-chip timers , serial interfaces , I²C bus, CAN bus or A / D converter .
The respective design of the processor core has become a highly specialized and optimized component over the years of processor development, which is specific to a manufacturing company and makes up the most complex part of the processor.
Processor cores can also be emulated in FPGA modules.
- Helmut Bähring: Microcomputer technology . Volume II, Volume 3, Springer Verlag, Berlin Heidelberg 2002, ISBN 3-540-43693-6 .
- Matthias Quantity: Modern processor architectures . Principles and their implementation, 1st edition, Springer Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 2004, ISBN 3-540-24390-9 .
- Helmut Bähring: Application-oriented microprocessors . Microcontrollers and digital signal processors, 4th edition, Springer Verlag, Heidelberg 2010, ISBN 978-3-642-12291-0 .