There are three major components of computer architecture. These are instruction set architecture, microarchitecture, and systems design. A microarchitecture is a digital logic that allows an instruction set to be executed. It fundamentally represents the manner in which a particular instruction set architecture is implemented in a computer processor.
Note that digital logic pertains to the manipulation of binary values through the design and implementation of a printed circuit board. On the other hand, an instruction set architecture or ISA is an abstract model of a computer that defines the set of instructions a microprocessor must support and how it is controlled by a software.
A Deeper Dive: What is a Microarchitecture
Understanding the Purpose
The purpose of microarchitecture generally centers on serving as the backbone or fundamental design of a microprocessor. It essentially represents the hardware circuitry that is responsible for implementing an instruction set architecture.
Hence, in other words, it is the hardware implementation of an ISA. Of course, a specific ISA may be interpreted with different microarchitectures. While it is true that an ISA defines the capabilities of a computer system, its implementation is as critical.
Remember that it is the basic design of a microprocessor. Included in the design are the specific design of the instruction pipeline and execution techniques, number and style of on-board caches as well as and caching techniques and type, and speed of the system bus.
Its specific roles include defining the size of the central processor, caching and defining cache size, pipelining, determining in-order versus out-order, speculative execution, determining socket type, super-scalar processing, and clock gating, among others.
An Overview of its Importance
To explain further the purpose of a microarchitecture, note that its design includes the identification and utilization of the process technology used in chipmaking or chip fabrication, as well as the materials used for transistors and other electronic components.
Processors that use older microarchitectures can still implement a particular ISA. However, they are theoretically and, in most cases, realistically outperformed by the most recent microarchitectures used in the latest generations of processors.
The most effective and efficient microprocessors would always be those with the most recent microarchitectural design. It is still possible that the latest microprocessor might perform poorly than an older one from another brand because of poor microarchitectural design.
Nevertheless, its importance centers on defining the capabilities of a microprocessor, especially in implementing a particular instruction set architecture. Furthermore, it can essentially make or break the overall capabilities of a computer system.
Examples of Microarchitecture
To understand further what a microarchitecture is, as well as its purpose and importance, take note of some of its notable examples. The x86 and x86-64 is an instruction set architecture based on the greater complex instruction set computer or CISC.
Most personal computers, including the majority of Windows-based computers, are based on CISC and x86 instruction sets, and they are implemented by different microarchitectures, such as those designed by Intel Corporation and Advanced Micro Devices or AMD.
Intel has been introducing regular generations of its Intel Core line of microprocessors. Examples include the Ivy Bridge, Haswell, Broadwell, Skylake, and Tiger Lake chips, and their respective microarchitectures such as Sunny Cove and Willow Cove. Each generation essentially corresponds to a new Intel microarchitecture.
Another example is the microarchitectures designed for Advanced RISC Machine or ARM family of reduced instruction set computer or RISC. These include the ARMv7-A and ARMv8-A used in several Qualcomm Snapdragon microprocessors.
The main high-performance Firestorm and energy-efficient Icestorm CPUs found on the Apple M1 series of system-on-chips, including the Apple M1 Pro and Apple M1 Max, the Apple-designed Mx microarchitecture, which is based on ARMv8.4-A