ARM Cortex A7 processor: characteristics and reviews. ARM processors versus x86: will there be a fight?

Hello our beloved readers. Today we will tell you about the architecture of the Cortex a53 processor.

You don't even realize how many of your gadgets work thanks to this processor. Few people know about the features of technology cores and what distinguishes them from each other. In this article you will learn about the features of a particular popular Cortex a53.

Characteristics

These processors can have from 1 to 8 cores, an L1 memory system and a shared L2 cache. To understand what distinguishes the main component of almost all equipment of this model from others, you need to know its advantages:

• High performance (supports a wide range of mobile applications, DTV, aerospace vehicles, storage and other similar equipment);
• High-quality Army8-A architecture for entry-level stand-alone designs;
• Universality (can be paired with any processors, such as Cortex-A72, Cortex-A57 and others);
• A quality product with a large loading capacity.

These are the main strengths of this product, but not all of its advantages. The core of this brand performs many functions:

• Supports up to 64bit and the latest architecture versions;
• TrustZone security technology;
• DSP and SIMD extensions;
• 8-stage conveyor with two outputs and improved integer;
• Can operate at frequencies from 1.5 GHz;
• Support for hardware virtualization.

This is a standard set of functions for this technical component, but these are not all the functions that this complex mechanism performs.

Where is it most often used?

Processors of this type are found not only in middle-class smartphones (Xiaomi redmi 4, Redmi 3s, Meizu m3/m5 Note, etc.), but also in the following technologies:

• Aerospace engineering;
• Net;
• Data storage (such as HDD, SDD);
• Car infotainment system;

Additional features

• Pipeline, which is responsible for low energy consumption;
• High throughput, which allows you to execute multiple commands simultaneously;
• Advanced energy saving features.

The processor is associated with different IPs

This technique is used in SoCs as well as Arm technologies, Graphics IP, System IP, and Physical IP. We provide you with a complete list of tools in which the core of this brand can be used :

• Mali-T860/Mali-T880;
• Mali-DP550;
• Mali-V550;
• CoreLink;
• Memory controller;
• Interrupt controller;
• DS-5 Development Studio;
• ARM compiler;
• Development boards;
• Fast models.

There are 2 types of Cortex a53 processors:

• AArch64 – allows you to install and use 64-bit applications;
• AArch32 – makes it possible to use only existing Armv7-A applications.

Why do you need all this technical information?

If you don't understand anything about technology and characteristics, then in simpler terms the Cortex a53 provides much greater performance than its predecessors with a higher level of energy efficiency. The core performance is even higher than that of the Cortex-A7 brand, which is found on many popular smartphones.

The Armv8-A architecture is what determines the functionality of the technologies. This brand of kernel has 64-bit data processing, extended virtual addressing and 64-bit general-purpose registers. All of these features made this processor the first that was designed specifically to provide power-efficient 64-bit processing.

Thus, you understand that the Cortex a53 processor is precisely the technical component that you should not skip when choosing equipment. If your smartphone has such a processor using this architecture, you don't have to worry about running out of memory or your phone draining quickly. All these problems are in the past.

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There was a site with you

The vast majority of modern gadgets use processors based on the ARM architecture, which is developed by the company of the same name ARM Limited. Interestingly, the company does not produce processors itself, but only licenses its technologies to third-party chip manufacturers. In addition, the company also develops Cortex processor cores and Mali graphics accelerators, which we will definitely touch on in this material.

ARM Limited

The ARM company, in fact, is a monopolist in its field, and the vast majority of modern smartphones and tablets on various mobile operating systems use processors based on the ARM architecture. Chip manufacturers license individual cores, instruction sets and related technologies from ARM, and the cost of licenses varies significantly depending on the type of processor cores (this can range from low-power budget solutions to cutting-edge quad-core and even eight-core chips) and additional components. ARM Limited's 2006 annual earnings report showed revenue of $161 million for licensing about 2.5 billion processors (up from 7.9 billion in 2011), which translates to approximately $0.067 per chip. However, for the reason stated above, this is a very average figure due to the difference in prices for various licenses, and since then the company’s profit should have grown many times over.

Currently, ARM processors are very widespread. Chips based on this architecture are used everywhere, including servers, but most often ARM can be found in embedded and mobile systems, from controllers for hard drives to modern smartphones, tablets and other gadgets.

Cortex cores

ARM develops several families of cores that are used for different tasks. For example, processors based on Cortex-Mx and Cortex-Rx (where “x” is a digit or number indicating the exact core number) are used in embedded systems and even consumer devices, such as routers or printers.

We will not dwell on them in detail, because we are primarily interested in the Cortex-Ax family - chips with such cores are used in the most productive devices, including smartphones, tablets and game consoles. ARM is constantly working on new cores from the Cortex-Ax line, but at the time of writing this article, the following are used in smartphones:

The higher the number, the higher the processor performance and, accordingly, the more expensive the class of devices in which it is used. However, it is worth noting that this rule is not always observed: for example, chips based on Cortex-A7 cores have higher performance than those based on Cortex-A8. However, if processors based on Cortex-A5 are already considered almost obsolete and are almost not used in modern devices, then CPUs based on Cortex-A15 can be found in flagship communicators and tablets. Not long ago, ARM officially announced the development of new, more powerful and, at the same time, energy-efficient Cortex-A53 and Cortex-A57 cores, which will be combined on one chip using ARM big.LITTLE technology and support the ARMv8 instruction set (“architecture version”) , but they are not currently used in mainstream consumer devices. Most Cortex-core chips can be multi-core, and quad-core processors are common in today's high-end smartphones.

Large manufacturers of smartphones and tablets usually use processors from well-known chipmakers like Qualcomm or their own solutions that have already become quite popular (for example, Samsung and its family of Exynos chipsets), but among the technical characteristics of gadgets from most small companies you can often find a description like “processor based on Cortex-A7 clocked at 1 GHz” or “dual-core Cortex-A7 clocked at 1 GHz”, which won’t mean anything to the average user. In order to understand what the differences between such nuclei are, let’s focus on the main ones.

The Cortex-A5 core is used in low-cost processors for the most budget devices. Such devices are intended only for performing a limited range of tasks and running simple applications, but are not at all designed for resource-intensive programs and, especially, games. An example of a gadget with a Cortex-A5 processor is the Highscreen Blast, which received a Qualcomm Snapdragon S4 Play MSM8225 chip containing two Cortex-A5 cores clocked at 1.2 GHz.

Cortex-A7 processors are more powerful than Cortex-A5 chips and are also more common. Such chips are manufactured using a 28-nanometer process technology and have a large second-level cache of up to 4 megabytes. Cortex-A7 cores are found mainly in budget smartphones and low-cost mid-segment devices like the iconBIT Mercury Quad, and also, as an exception, in the Samsung Galaxy S IV GT-i9500 with an Exynos 5 Octa processor - this chipset uses energy-saving technology when performing undemanding tasks. quad-core Cortex-A7 processor.

The Cortex-A8 core is not as widespread as its neighbors, Cortex-A7 and Cortex-A9, but is still used in various entry-level gadgets. The operating clock speed of Cortex-A8 chips can range from 600 MHz to 1 GHz, but sometimes manufacturers overclock processors to higher frequencies. A feature of the Cortex-A8 core is the lack of support for multi-core configurations (that is, processors on these cores can only be single-core), and they are executed using a 65-nanometer process technology, which is already considered obsolete.

Сortex-A9

Just a couple of years ago, Cortex-A9 cores were considered a top solution and were used in both traditional single-core and more powerful dual-core chips, such as Nvidia Tegra 2 and Texas Instruments OMAP4. Currently, Cortex-A9 processors made using the 40-nanometer process technology are not losing popularity and are used in many mid-segment smartphones. The operating frequency of such processors can be from 1 to 2 or more gigahertz, but it is usually limited to 1.2-1.5 GHz.

In June 2013, ARM officially introduced the Cortex-A12 core, which is manufactured using a new 28-nanometer process technology and is designed to replace Cortex-A9 cores in mid-segment smartphones. The developer promises a 40% increase in performance compared to Cortex-A9, and in addition, Cortex-A12 cores will be able to participate in the ARM big.LITTLE architecture as productive ones along with energy-saving Cortex-A7, which will allow manufacturers to create inexpensive eight-core chips. True, at the time of writing, all this is only in plans, and mass production of Cortex-A12 chips has not yet been established, although RockChip has already announced its intention to release a quad-core Cortex-A12 processor with a frequency of 1.8 GHz.

As of 2013, the Cortex-A15 core and its derivatives are the top solution and are used in flagship communicator chips from various manufacturers. Among the new processors made using a 28-nm process technology and based on Cortex-A15 are Samsung Exynos 5 Octa and Nvidia Tegra 4, and this core often acts as a platform for modifications from other manufacturers. For example, Apple's latest A6X processor uses Swift cores, which are a modification of Cortex-A15. Chips based on Cortex-A15 are capable of operating at a frequency of 1.5-2.5 GHz, and support for many third-party standards and the ability to address up to 1 TB of physical memory makes it possible to use such processors in computers (how can one not recall a mini-computer the size of a bank Raspberry Pi card).

Cortex-A50 series

In the first half of 2013, ARM introduced a new line of chips called the Cortex-A50 series. The cores of this line will be made according to a new version of the architecture, ARMv8, and will support new instruction sets, and will also become 64-bit. The transition to a new bit depth will require optimization of mobile operating systems and applications, but, of course, support for tens of thousands of 32-bit applications will remain. Apple was the first to switch to 64-bit architecture. The company's latest devices, for example, the iPhone 5S, run on exactly this Apple A7 ARM processor. Notably, it does not use Cortex cores - they are replaced with the manufacturer's own cores called Swift. One of the obvious reasons for the need to move to 64-bit processors is the support of more than 4 GB of RAM, and, in addition, the ability to handle much larger numbers when calculating. Of course, for now this is relevant, first of all, for servers and PCs, but we will not be surprised if in a few years smartphones and tablets with such an amount of RAM appear on the market. To date, nothing is known about plans to produce chips on the new architecture and smartphones using them, but it is likely that flagships will receive exactly these processors in 2014, as Samsung has already announced.

The series opens with the Cortex-A53 core, which will be the direct “successor” of the Cortex-A9. Processors based on Cortex-A53 are noticeably superior to chips based on Cortex-A9 in performance, but at the same time maintain low power consumption. Such processors can be used either individually or in an ARM big.LITTLE configuration, being combined on the same chipset with a Cortex-A57 processor

Performance Cortex-A53, Cortex-A57

Cortex-A57 processors, which will be manufactured using a 20-nanometer process technology, should become the most powerful ARM processors in the near future. The new core is significantly superior to its predecessor, Cortex-A15, in various performance parameters (you can see the comparison above), and, according to ARM, which is seriously targeting the PC market, it will be a profitable solution for regular computers (including laptops), not just mobile ones devices.

ARM big.LITTLE

As a high-tech solution to the problem of energy consumption of modern processors, ARM offers big.LITTLE technology, the essence of which is to combine different types of cores on one chip, usually the same number of energy-saving and high-performance ones.

There are three schemes for operating different types of cores on one chip: big.LITTLE (migration between clusters), big.LITTLE IKS (migration between cores) and big.LITTLE MP (heterogeneous multiprocessing).

big.LITTLE (migration between clusters)

The first chipset based on the ARM big.LITTLE architecture was the Samsung Exynos 5 Octa processor. It uses the original big.LITTLE “4+4” scheme, which means combining into two clusters (hence the name of the scheme) on one chip four high-performance Cortex-A15 cores for resource-intensive applications and games and four energy-saving Cortex-A7 cores for everyday work with most programs, and only one type of kernel can work at one time. Switching between groups of cores occurs almost instantly and unnoticed by the user in a fully automatic mode.

big.LITTLE IKS (migration between cores)

A more complex implementation of the big.LITTLE architecture is the combination of several real cores (usually two) into one virtual one, controlled by the operating system kernel, which decides which cores to use - energy-efficient or productive. Of course, there are also several virtual cores - the illustration shows an example of the IKS scheme, where each of the four virtual cores contains one Cortex-A7 and Cortex-A15 core.

big.LITTLE MP (heterogeneous multiprocessing)

The big.LITTLE MP scheme is the most “advanced” - in it, each core is independent and can be turned on by the OS kernel as needed. This means that if four Cortex-A7 cores and the same number of Cortex-A15 cores are used, a chipset built on the ARM big.LITTLE MP architecture will be able to run all 8 cores simultaneously, even though they are of different types. One of the first processors of this type was the eight-core chip from Mediatek - MT6592, which can operate at a clock frequency of 2 GHz, and also record and play video in UltraHD resolution.

Future

According to currently available information, in the near future ARM, together with other companies, plans to launch the next generation big.LITTLE chips, which will use the new Cortex-A53 and Cortex-A57 cores. In addition, the Chinese manufacturer MediaTek is going to produce budget processors based on ARM big.LITTLE, which will operate according to the “2+2” scheme, that is, use two groups of two cores.

Mali graphics accelerators

In addition to processors, ARM also develops graphics accelerators of the Mali family. Like processors, graphics accelerators are characterized by many parameters, for example, the level of anti-aliasing, bus interface, cache (ultra-fast memory used to increase operating speed) and the number of “graphics cores” (although, as we wrote in the previous article, this indicator, despite the similarity with the term used to describe the CPU has virtually no impact on performance when comparing two GPUs).

The first ARM graphics accelerator was the now-unused Mali 55, which was used in the LG Renoir touch phone (yes, the most common cell phone). The GPU was not used in games - only for rendering the interface, and had primitive characteristics by today's standards, but it became the “ancestor” of the Mali series.

Since then, progress has come a long way, and now supported APIs and gaming standards are of considerable importance. For example, support for OpenGL ES 3.0 is now announced only in the most powerful processors like Qualcomm Snapdragon 600 and 800, and, if we talk about ARM products, the standard is supported by accelerators such as the Mali-T604 (it was the first ARM GPU made on new Midgard microarchitecture), Mali-T624, Mali-T628, Mali-T678 and some other chips similar in characteristics. This or that GPU, as a rule, is closely related to the kernel, but, nevertheless, is indicated separately, which means that if the quality of graphics in games is important to you, then it makes sense to look at the name of the accelerator in the specifications of the smartphone or tablet.

ARM also has graphics accelerators for mid-segment smartphones in its lineup, the most common of which are Mali-400 MP and Mali-450 MP, which differ from their older brothers in relatively low performance and a limited set of APIs and supported standards. Despite this, these GPUs continue to be used in new smartphones, for example, Zopo ZP998, which received the Mali-450 MP4 graphics accelerator (an improved modification of the Mali-450 MP) in addition to the eight-core MTK6592 processor.

Presumably, smartphones with the latest ARM graphics accelerators should appear at the end of 2014: Mali-T720, Mali-T760 and Mali-T760 MP, which were introduced in October 2013. The Mali-T720 is slated to be the new GPU for low-cost smartphones and the first GPU in this segment to support Open GL ES 3.0. The Mali-T760, in turn, will become one of the most powerful mobile graphics accelerators: according to the stated characteristics, the GPU has 16 computing cores and has truly enormous computing power, 326 Gflops, but, at the same time, four times less power consumption than the Mali-T604 mentioned above.

The role of CPUs and GPUs from ARM in the market

Despite the fact that ARM is the author and developer of the architecture of the same name, which, we repeat, is now used in the vast majority of mobile processors, its solutions in the form of cores and graphics accelerators are not popular with major smartphone manufacturers. For example, it is rightly believed that flagship communicators on Android OS should have a Snapdragon processor with Krait cores and an Adreno graphics accelerator from Qualcomm; chipsets from the same company are used in smartphones on Windows Phone, and some gadget manufacturers, for example, Apple, develop their own cores . Why does this situation currently exist?

Perhaps some of the reasons may lie deeper, but one of them is the lack of a clear positioning of CPUs and GPUs from ARM among the products of other companies, as a result of which the company's developments are perceived as basic components for use in B-brand devices, inexpensive smartphones and the creation of more mature solutions. For example, Qualcomm repeats at almost every presentation that one of its main goals when creating new processors is to reduce power consumption, and its Krait cores, being modified Cortex cores, consistently show higher performance results. A similar statement is true for Nvidia chipsets, which are focused on games, but as for Exynos processors from Samsung and A-series from Apple, they have their own market due to installation in smartphones of the same companies.

The above does not mean at all that ARM’s developments are significantly worse than processors and cores from third-party companies, but competition in the market ultimately only benefits smartphone buyers. We can say that ARM offers some blanks, by purchasing a license for which, manufacturers can independently modify them.

Conclusion

Microprocessors based on ARM architecture have successfully conquered the mobile device market due to their low power consumption and relatively high computing power. Previously, other RISC architectures competed with ARM, for example, MIPS, but now it has only one serious competitor left - Intel with the x86 architecture, which, by the way, although it is actively fighting for its market share, is not yet perceived by either consumers or by most manufacturers seriously, especially given the virtual absence of flagships based on it (Lenovo K900 can no longer compete with the latest top-end smartphones on ARM processors).

What do you think, will anyone be able to supplant ARM, and what will be the future of this company and its architecture?

The computer world is changing rapidly. Desktop PCs have lost first place in the sales rankings to laptops, and they are about to give the market to tablets and other mobile devices. 10 years ago we valued pure megahertz, true power and performance. Now, in order to conquer the market, the processor must be not only fast, but also economical. Many people believe that ARM is the architecture of the 21st century. Is it so?

New - well forgotten old

Journalists, following ARM PR people, often present this architecture as something completely new that should bury the gray-haired x86.

In fact, ARM and x86, on the basis of which the Intel, AMD and VIA processors installed in laptops and desktop PCs are built, are almost the same age. The first x86 chip was released in 1978. The ARM project officially started in 1983, but was based on developments that were carried out almost simultaneously with the creation of the x86.

The first ARMs impressed specialists with their elegance, but with their relative low performance they could not conquer a market that demanded high speeds and did not pay attention to efficiency. Certain conditions had to exist for ARM's popularity to skyrocket.

At the turn of the eighties and nineties, with their relatively inexpensive oil, huge SUVs with powerful 6-liter engines were in demand. Few people were interested in electric cars. But in our time, when a barrel of oil costs more than $100, large cars with power-hungry engines are needed only by the rich; the rest are in a hurry to switch to economical cars. A similar thing happened with ARM. When the question of mobility and efficiency arose, architecture turned out to be in great demand.

"Risk" processor

ARM is a RISC architecture. It uses a reduced set of commands – RISC (reduced instruction set computer). This type of architecture appeared in the late seventies, around the same time that Intel offered its x86.

While experimenting with various compilers and microcode processors, engineers noticed that in some cases, sequences of simple commands were executed faster than a single complex operation. It was decided to create an architecture that would involve working with a limited set of simple instructions, the decoding and execution of which would take a minimum of time.

One of the first RISC processor projects was carried out by a group of students and teachers at the University of Berkeley in 1981. Just at this time, the British company Acorn faced the challenge of time. It produced BBC Micro educational computers based on the 6502 processor, which were very popular in Foggy Albion. But soon these home PCs began to lose to more advanced machines. Acorn was at risk of losing the market. The company's engineers, having become acquainted with student work on RISC processors, decided that creating their own chip would be quite simple. In 1983, the Acorn RISC Machine project was launched, which later became ARM. Three years later the first processor was released.

First ARM

He was extremely simple. The first ARM chips even lacked multiply and divide instructions, which were represented by a set of simpler instructions. Another feature of the chips was the principles of working with memory: all operations with data could be carried out only in registers. At the same time, the processor worked with the so-called register window, that is, it could access only a part of all available registers, which were mainly universal, and their operation depended on the mode in which the processor was located. This made it possible to abandon the cache in the very first versions of ARM.

In addition, by simplifying instruction sets, architecture developers were able to do without a number of other blocks. For example, the first ARMs completely lacked microcode, as well as a floating point unit (FPU). The total number of transistors in the first ARM was 30,000. In similar x86s there were several times, or even an order of magnitude more. Additional energy savings are achieved through conditional execution of commands. That is, this or that operation will be performed if there is a corresponding fact in the register. This helps the processor avoid “unnecessary movements”. All instructions are executed sequentially. As a result, ARM lost in performance, but not significantly, while gaining significantly in power consumption.

The basic principles of the architecture remain the same as in the first ARM: working with data only in registers, a reduced set of instructions, a minimum of additional modules. All this provides the architecture with low power consumption and relatively high performance.

In order to increase this, ARM has introduced several additional instruction sets in recent years. Along with the classic ARM, there are Thumb, Thumb 2, Jazelle. The latter is designed to speed up the execution of Java code.

Cortex - the most advanced ARM

Cortex – modern architectures for mobile devices, embedded systems and microcontrollers. Accordingly, CPUs are designated as Cortex-A, embedded – Cortex-R and microcontrollers – Cortex-M. All of them are built on the ARMv7 architecture.

The most advanced and powerful architecture in the ARM line is Cortex-A15. It is assumed that mainly two- or four-core models will be produced on its basis. Cortex-A15 of all previous ARMs is closest to x86 in terms of the number and quality of blocks.

The Cortex-A15 is based on processor cores equipped with an FPU unit and a set of NEON SIMD instructions designed to speed up the processing of multimedia data. The cores have a 13-stage pipeline, they support free-order instruction execution, and ARM-based virtualization.

Cortex-A15 supports advanced memory addressing system. ARM remains a 32-bit architecture, but the company's engineers have learned to convert 64-bit or other advanced addressing into processor-friendly 32-bit. The technology is called Long Physical Address Extensions. Thanks to it, Cortex-A15 can theoretically address up to 1 TB of memory.

Each core is equipped with a first-level cache. In addition, there is up to 4 MB of distributed low-latency L2 cache. The processor is equipped with a 128-bit coherent bus, which can be used to communicate with other units and peripherals.

The cores that underlie Cortex-A15 are a development of Cortex-A9. They have a similar structure.

Cortex-A9, unlike Cortex-A15, can be produced in both multi- and single-core versions. The maximum frequency is 2.0 GHz, Cortex-A15 suggests the possibility of creating chips operating at a frequency of 2.5 GHz. Chips based on it will be manufactured using 40 nm and thinner technical processes. Cortex-A9 is produced in 65 and 40 nm process technologies.

Cortex-A9, like Cortex-A15, is intended for use in high-performance smartphones and tablets, but it is not suitable for more serious applications, for example, in servers. Only Cortex-A15 has hardware virtualization, advanced memory addressing. In addition, the NEON Advanced SIMD instruction set and FPU are optional in the Cortex-A9, while they are required in the Cortex-A15.

Cortex-A8 will gradually disappear from the scene in the future, but for now this single-core variant will find use in budget smartphones. The low-cost solution, with frequencies ranging from 600 MHz to 1 GHz, provides a balanced architecture. It has an FPU unit and supports the first version of SIMD NEON. Cortex-A8 assumes a single technological process - 65 nm.

ARM of previous generations

ARM11 processors are quite common in the mobile market. They are built on the basis of the ARMv6 architecture and its modifications. It is characterized by 8-9-stage pipelines, Jazelle support, which helps speed up the processing of Java code, SIMD stream instructions, Thumb-2.

XScale, ARM10E, ARM9E processors are based on the ARMv5 architecture and its modifications. Maximum pipeline length is 6 stages, Thumb, Jazelle DBX, Enhanced DSP. XScale chips have a second level cache. The processors were used in smartphones of the mid-2000s; today they can be found in some inexpensive mobile phones.

ARM9TDMI, ARM8, StrongARM - representatives of ARMv4, which has a 3-5 stage pipeline and supports Thumb. ARMv4, for example, could be found in the first classic iPods.

ARM6 and ARM7 belong to ARMv3. In this architecture, the FPU unit appeared for the first time; 32-bit memory addressing was implemented, and not 26-bit, as in the first examples of the architecture. ARMv2 and ARMv1 were technically 32-bit chips, but in reality only actively worked with a 26-bit address space. The cache first appeared in ARMv2.

Their name is legion

Acorn did not initially intend to become a player in the processor market. The task of the ARM project was to create a chip of its own production for the production of computers - it was the creation of PCs that Acorn considered its main business.

ARM has evolved from a development group into a company thanks to Apple. In 1990, Apple, together with VLSI and Acorn, began developing a low-cost processor for the first pocket computer, the Newton. For these purposes, a separate company was created, which received the name of the internal project Acorn - ARM.

With the participation of Apple, an ARM6 processor was created, which is closest to modern chips from an English developer. At the same time, DEC was able to patent the ARM6 architecture and began producing chips under the StrongARM brand. A couple of years later, the technology was transferred to Intel as part of another patent dispute. The microprocessor giant created its analogue, the XScale processor, based on ARM. But in the middle of the previous decade, Intel got rid of this “non-core asset”, focusing exclusively on x86. XScale moved into the hands of Marvell, which already licensed ARM.

At first, ARM, which was new to the world, was not able to produce processors. Its management chose a different way of making money. The ARM architecture was simple and flexible. At first, the core was devoid of even a cache, so subsequently additional modules, including FPU, controllers were not closely integrated into the processor, but were, as it were, hung on the base.

Accordingly, ARM got its hands on an intelligent designer that allowed technologically advanced companies to create processors or microcontrollers to suit their needs. This is done using so-called coprocessors, which can expand the standard functionality. In total, the architecture supports up to 16 coprocessors (numbers from 0 to 15), but number 15 is reserved for the coprocessor that performs cache and memory management functions.

Peripherals connect to the ARM chip, mapping their registers to the memory space of the processor or coprocessor. For example, an image processing chip may consist of a relatively simple ARM7TDMI-based core and a coprocessor that provides HDTV signal decoding.

ARM began licensing its architecture. Other companies have already been implementing it in silicon, including Texas Instruments, Marvell, Qualcomm, Freescale, but also completely non-core ones like Samsung, Nokia, Nintendo or Canon.

The absence of its own factories, as well as impressive licensing fees, allowed ARM to be more flexible in developing new versions of the architecture. The company baked them like hot cakes, entering new niches. In addition to smartphones and tablets, the architecture is used in specialized processors, for example, in GPS navigators, digital cameras and video cameras. Industrial controllers and other chips for embedded systems are created on its basis.

The ARM licensing system is a real microelectronics hypermarket. The company licenses not only new but also legacy architectures. The latter can be used to create microcontrollers or chips for low-cost devices. Naturally, the level of licensing fees depends on the degree of novelty and complexity of the architecture variant of interest to the manufacturer. Traditionally, the technical processes for which ARM develops processors are 1-2 steps behind those that are considered relevant for x86. The high energy efficiency of the architecture makes it less dependent on the transition to new technological standards. Intel and AMD are striving to make thinner chips in order to increase frequencies and the number of cores while maintaining physical size and power consumption. ARM inherently has lower power requirements and also delivers higher levels of performance per watt.

Features of NVIDIA, TI, Qualcomm, Marvell processors

By licensing ARM left and right, developers strengthened the position of their architecture at the expense of the competencies of their partners. A classic example in this case is NVIDIA Tegra. This line of systems-on-chip is based on ARM architecture, but NVIDIA already had its own very serious developments in the field of 3D graphics and system logic.

ARM gives its licensors broad discretion to redesign the architecture. Accordingly, NVIDIA engineers were able to combine in Tegra the strengths of ARM (CPU computing) and their own products - working with three-dimensional graphics, etc. As a result, Tegra has the highest 3D performance for its class of processors. They are 25-30% faster than PowerVR, used by Samsung and Texas Instruments, and are almost twice as fast as Adreno, developed by Qualcomm.

Other manufacturers of processors based on the ARM architecture are strengthening certain additional blocks and improving chips to achieve higher frequencies and performance.

For example, Qualcomm does not use the ARM reference design. The company's engineers seriously reworked it and called it Scorpio - it is the basis of Snapdragon chips. The design has been partly redesigned to accommodate more sophisticated technical processes than those provided by the standard IP ARM. As a result, the first Snapdragons were produced at 45 nm, which provided them with higher frequencies. And the new generation of these processors with a declared 2.5 GHz may even become the fastest among analogues based on ARM Cortex-A9. Qualcomm also uses its own Adreno graphics core, created on the basis of developments purchased from AMD. So in a way, Snapdragon and Tegra are enemies on a genetic level.

When creating Hummingbird, Samsung also took the path of optimizing the architecture. The Koreans, together with the Intrinsity company, changed the logic, thereby reducing the number of instructions required to perform certain operations. Thus, we managed to gain 5-10% of productivity. In addition, a dynamic L2 cache and ARM NEON multimedia extension were added. The Koreans used PowerVR SGX540 as a graphics module.

Texas Instruments in its new OMAP series based on the ARM Cortex-A architecture has added a special IVA module responsible for accelerating image processing. It allows you to quickly process data coming from the sensor to the built-in camera. In addition, it is connected to the ISP and helps in video acceleration. OMAP also uses PowerVR graphics.

The Apple A4 has a large 512 KB cache, uses PowerVR graphics, and the ARM core itself is built on a variant of the architecture redesigned by Samsung.

The dual-core Apple A5, which debuted in the iPad 2 in early 2011, is based on the ARM Cortex-A9 architecture, just like the one previously optimized by Samsung. Compared to the A4, the new chip has double the amount of second-level cache memory - it has been increased to 1 MB. The processor contains a dual-channel RAM controller and has an improved video unit. As a result, it performs twice as well as the Apple A4 in some tasks.

Marvell offers chips based on its own Sheeva architecture, which, upon closer inspection, turns out to be a hybrid of XScale, once purchased from Intel, and ARM. These chips have a larger amount of cache memory compared to analogues and are equipped with a special multimedia module.

Currently, ARM licensees only produce chips based on the ARM Cortex-A9 architecture. At the same time, although it allows you to create quad-core variants, NVIDIA, Apple, Texas Instruments and others are still limited to models with one or two cores. In addition, the chips operate at frequencies up to 1.5 GHz. Cortex-A9 allows you to make two-GHz processors, but again, manufacturers are not trying to quickly increase frequencies - after all, for now the market will have enough dual-core processors at 1.5 GHz.

Processors based on Cortex-A15 should become truly multi-core, but even if they are announced, they are only on paper. Their appearance in silicon should be expected next year.

Modern ARM licensee processors based on Cortex-A9:

x86 is the main contender

x86 is a representative of CISC architectures. They use the full set of commands. One instruction in this case performs several low-level operations. The program code, unlike ARM, is more compact, but does not execute as quickly and requires more resources. In addition, from the very beginning, x86 were equipped with all the necessary blocks, which implied both their versatility and gluttony. Additional energy was spent on unconditional, parallel execution of commands. This allows you to achieve a speed advantage, but some operations are performed in vain because they do not satisfy the previous conditions.

These were the classic x86s, but starting with the 80486, Intel de facto created an internal RISC core that executed CISC instructions, previously decomposed into simpler instructions. Modern Intel and AMD processors have the same design.

Windows 8 and ARM

ARM and x86 today differ less than 30 years ago, but are still based on different principles, which separates them into different niches of the processor market. The architectures might never have intersected if the computer itself had not changed.

Mobility and cost-effectiveness came first, and more attention was paid to smartphones and tablets. Apple makes a lot of money from mobile gadgets and the infrastructure tied to them. Microsoft does not want to be left behind and has been trying to gain a foothold in the tablet market for the second year. Google is quite successful.

The desktop PC is becoming primarily a working tool; the niche of the household computer is occupied by tablets and specialized devices. In these conditions, Microsoft is going to take an unprecedented step. . It is not yet entirely clear what this will lead to. We will get two versions of the operating system, or one that will work with both architectures. Will Microsoft's ARM support kill x86 or not?

There is little information yet. Microsoft demonstrated Windows 8 running on a device with an ARM processor during CES 2011. Steve Ballmer showed that on the ARM platform using Windows you can watch videos, work with images, surf the Internet - Internet Explorer even worked with hardware acceleration - connect USB- devices, print documents. The most important thing about this demo was the presence of Microsoft Office running on ARM without the participation of a virtual machine. At the presentation, three gadgets based on processors from Qualcomm, Texas Instruments and NVIDIA were shown. Windows had a standard “seven” shell, but Microsoft representatives announced a new, redesigned system kernel.

However, Windows is not only an OS made by Microsoft engineers, it is also millions of programs. Some software is critical for people in many professions. For example, the Adobe CS package. Will the company support an ARM-Windows version of the software, or will the new kernel allow Photoshop and other popular applications to run on computers with NVIDIA Tegra or other similar chips without additional code modifications?

In addition, the question arises with video cards. Nowadays, video cards for laptops are made by optimizing the power consumption of desktop graphics chips - they are architecturally the same. At the same time, now a video card is something like a “computer within a computer” - it has its own ultra-fast RAM and its own computing chip, which is significantly superior to conventional processors in specific tasks. It goes without saying that applications that work with 3D graphics have been appropriately optimized for them. Yes, and various video editing programs and graphic editors (in particular Photoshop from version CS4), and more recently also browsers use hardware acceleration using GPUs.

Of course, in Android, MeeGo, BlackBerry OS, iOS and other mobile systems, the necessary optimization has been made for the various mobile (more precisely, ultra-mobile) accelerators on the market. However, they are not supported in Windows. Drivers, of course, will be written (and have already been written - Intel Atom Z500 series processors come with a chipset that integrates the PowerVR SGX 535 “smartphone” graphics core), but optimization of applications for them may be late, if at all.

Obviously, “ARM on the desktop” won’t really catch on. Perhaps in low-power systems on which they will access the Internet and watch movies. On nettops in general. So ARM is so far only trying to take aim at the niche that Intel Atom occupied and where AMD is now actively pursuing with its Brazos platform. And she, apparently, will partially succeed. Unless both processor companies come up with something very competitive.

In some places, Intel Atom and ARM are already competing. They are used to create networked data storage and low-power servers that can serve a small office or apartment. There are also several commercial projects of clusters based on cost-effective Intel chips. The characteristics of the new processors based on ARM Cortex-A9 allow them to be used to support infrastructure. Thus, in a couple of years we may get ARM servers or ARM-NAS for small local networks, and the emergence of low-power web servers cannot be ruled out.

First sparring

ARM's main competitor from the x86 side is Intel Atom, and now we can add the . A comparison of x86 and ARM was carried out by Van Smith, who created the OpenSourceMark, miniBench test packages and one of the co-authors of SiSoftware Sandra. Atom N450, Freescale i.MX515 (Cortex-A8), VIA Nano L3050 took part in the “race”. The frequencies of x86 chips were reduced, but they still had an advantage due to more advanced memory.

The results turned out to be very interesting. The ARM chip turned out to be as fast as its competitors in integer operations, while consuming less power. There is nothing surprising here. Initially, the architecture was both quite fast and economical. In floating point operations, ARM was inferior to x86. The traditionally powerful FPU unit found in Intel and AMD chips had an impact here. Let us remember that it appeared in ARM relatively recently. The tasks that fall on the FPU occupy a significant place in the life of a modern user - these are games, video and audio encoding, and other streaming operations. Of course, the tests conducted by Van Smith are no longer so relevant today. ARM has significantly strengthened the weaknesses of its architecture in versions of Cortex-A9 and especially Cortex-A15, which, for example, can already execute instructions unconditionally, parallelizing problem solving.

Prospects for ARM

So which architecture should you choose in the end, ARM or x86? It would be most correct to bet on both. Today we live in conditions of reformatting of the computer market. In 2008, netbooks were predicted to have a bright future. Cheap compact laptops were supposed to become the main computer for most users, especially against the backdrop of the global crisis. But then the economy started to recover and the iPad came out. Now tablets are declared kings of the market. However, the tablet is good as an entertainment console, but not very convenient for work, primarily due to touch input - writing this article on an iPad would be very difficult and time-consuming. Will tablets stand the test of time? Perhaps in a couple of years we will come up with a new toy.

But still, in the mobile segment, where high performance is not required, and user activity is mainly limited to entertainment and not related to work, ARM looks preferable to x86. They provide an acceptable level of performance, as well as long battery life. Intel's attempts to bring Atom to fruition have so far been unsuccessful. ARM sets a new benchmark for performance per watt. Most likely, ARM will be successful in compact mobile gadgets. They can also become leaders in the netbook market, but here everything depends not so much on processor developers as on Microsoft and Google. If the first implements normal ARM support in Windows 8, and the second brings Chrome OS to fruition. So far, the smartbooks proposed by Qualcomm have not made it into the market. Netbooks based on x86 survived.

According to ARM, a breakthrough in this direction should be made by the Cortex-A15 architecture. The company recommends dual- and quad-core processors based on it with a frequency of 1.0-2.0 GHz for home entertainment systems that will combine a media player, a 3D TV and an Internet terminal. Quad-core chips with a frequency of 1.5-2.5 GHz can become the basis of home and web servers. Finally, the most ambitious use case for Cortex-A15 is wireless network infrastructure. Chips with four or more cores and a frequency of 1.5-2.5 GHz can be used here.

But for now these are just plans. Cortex-A15 was introduced by ARM in September last year. Cortex-A9 was shown by the company in October 2007, two years later the company presented the A9 variant with the ability to increase the frequency of the chips to 2.0 GHz. For comparison, NVIDIA Tegra 2 - one of the most popular solutions based on Cortex-A9 - was released only in January last year. Well, users were able to touch the first gadgets based on it after another six months.

The work PC segment and high-performance solutions will remain with x86. This will not mean the death of the architecture, but in monetary terms, Intel and AMD should prepare for the loss of part of the income that will go to ARM processor manufacturers.

They thought that since a group of students managed to create a completely competitive processor, then it would not be difficult for their engineers. A trip to the Western Design Center in Phoenix showed engineers Steve Ferber and Sophie Wilson that they wouldn't need incredible resources to pull off the plan.

Wilson began developing the instruction set by creating a simulator of the new processor on a BBC Micro computer. This convinced Acorn engineers that they were on the right track. But still, before going further, they needed more resources. It was time for Wilson to approach Acorn CEO Herman Hauser and explain what was going on. After he gave the go-ahead, a small team assembled to implement Wilson's model in hardware.

Acorn RISC Machine: ARM2

The official Acorn RISC Machine project was started in October 1983. VLSI Technology ( English) was chosen as the silicon supplier because it already supplied Acorn with ROM chips and some custom integrated circuits. Wilson and Ferber led the development. Their main goal was to achieve low interrupt latency, similar to the MOS Technology 6502. The memory access architecture taken from the 6502 allowed developers to achieve good performance without using a DMA module that was expensive to implement. The first processor was produced by VLSI on April 26, 1985, when it first started working and was called ARM1. The first production processors, called ARM2, became available the following year.

Its first use was as a second processor at BBC Micro, where it was used in the development of simulation software that enabled the completion of computer support chips, as well as speeding up the CAD software used in the development of the ARM2. Wilson optimized the ARM instruction set to run BBC BASIC. The original goal of an all-ARM computer was achieved in 1987 with the release of Acorn Archimedes.

The atmosphere surrounding the ARM project was so secretive that when Olivetti negotiated to buy a majority stake in Acorn in 1985, they did not talk about the development of the project until the end of the negotiations. In 1992, Acorn once again won the Queen's Award for ARM.

ARM2 had a 32-bit data bus, a 26-bit address space, and 16 32-bit registers. The program code had to be in the first 64 megabytes of memory, and the program counter was limited to 26 bits, since the top 4 and bottom 2 bits of the 32-bit register served as flags. ARM2 became perhaps the simplest popular 32-bit processor in the world, with only 30,000 transistors (for comparison, the Motorola 68000 processor made 6 years earlier had about 70,000 transistors). Much of this simplicity is due to the absence of microcode (which in the 68000 processor takes up one-quarter to one-third of the die area), and the absence of a cache, as in many processors of the time. This simplicity resulted in low power costs, while the ARM was much more efficient than the Intel 80286. Its successor, the ARM3 processor, already had a 4 KB cache, increasing performance even further.

Apple, DEC, Intel: ARM6, StrongARM, XScale

Modern smartphones, PDAs and other portable devices mainly use the ARMv5 version of the kernel. XScale and ARM926 (ARMv5TE) processors are now more common in high-end devices than, for example, StrongARM processors and ARM9TDMI- and ARM7TDMI-based ARMv4 processors, but less complex devices may use older versions with lower licensing costs. ARMv6 processors are head and shoulders above standard ARMv5 processors. Cortex-A is designed specifically for smartphones that previously used ARM9 and ARM11. Cortex-R is designed for real-time applications, while Cortex-M is designed for microcontrollers.

Impact of ARM technology on the market

By the end of 2012, new models of ARM processors from Apple and Samsung reached the performance of budget Intel processors for laptops. In particular, the Samsung Nexus 10 tablet showed a performance rating of 2348 points, while the budget Intel Core Duo processor in the Apple MacAir laptop showed a rating of only 1982 points.

Some companies are announcing the development of efficient servers based on clusters of ARM processors. However, as of 2012, sales of ARM servers are vanishingly small (< 1% рынка серверов) .

ARM processors

Kernel family	Architecture version	Core	Functions	Cache (I/D)/MMU	Typical MIPS @ MHz	Usage
ARM1	ARMv1 (obsolete)	ARM1		No		ARM Evaluation System processor BBC Micro
ARM2	ARMv2 (obsolete)	ARM2	Added MUL (multiply) command	No	4 MIPS @ 8 MHz 0.33 DMIPS/MHz	Acorn Archimedes, Chessmachine
	ARMv2a (obsolete)	ARM250	Built-in MEMC (MMU), GPU, added SWP and SWPB (swap) commands	No, MEMC1a	7 MIPS @ 12 MHz	Acorn Archimedes
ARM3	ARMv2a (obsolete)	ARM2a	Cache used for the first time	4 KB shared	12 MIPS @ 25 MHz 0.50 DMIPS/MHz	Acorn Archimedes
ARM6	ARMv3 (obsolete)	ARM60	32-bit (rather than 26-bit) memory address space introduced for the first time	No	10 MIPS @ 12 MHz	3DO Interactive Multiplayer, Zarlink GPS Receiver
		ARM600	Like ARM60, FPA10 floating point math coprocessor	4 KB shared	28 MIPS @ 33 MHz
		ARM610	Like ARM60, cache, no coprocessor bus	4 KB shared	17 MIPS @ 20 MHz 0.65 DMIPS/MHz	Acorn Risc PC 600, Apple Newton 100 series
ARM7	ARMv3 (obsolete)	ARM700		8 KB total	40 MHz
		ARM710	Like ARM700	8 KB total	40 MHz	Acorn Risc PC 700
		ARM710a	Like ARM700	8 KB total	40 MHz 0.68 DMIPS/MHz	Acorn Risc PC 700, Apple eMate 300
		ARM7100	Like ARM710a integrated SoC	8 KB total	18 MHz	Psion Series 5
		ARM7500	Like ARM710a integrated SoC.	4 KB shared	40 MHz	Acorn A7000
		ARM7500FE	Like ARM7500, "FE" added FPA and EDO memory controllers	4 KB shared	56 MHz 0.73 DMIPS/MHz	Acorn A7000+ Network Computer
ARM7TDMI	ARMv4T	ARM7TDMI(-S)	3-stage conveyor, Thumb mode	No	15 MIPS @ 16.8 MHz 63 DMIPS @ 70 MHz	Game Boy Advance, Nintendo DS, Apple iPod, Lego NXT, Atmel AT91SAM7, Juice Box, NXP Semiconductors LPC2000 and LH754xx, Actel's CoreMP7
		ARM710T	Like ARM7TDMI, cache	8 KB shared, MMU	36 MIPS @ 40 MHz	Psion Series 5mx, Psion Revo/Revo Plus/Diamond Mako
		ARM720T	Like ARM7TDMI, cache	8 KB shared, MMU with fast context switching extension (English) Fast Context Switch Extension)	60 MIPS @ 59.8 MHz	Zipit Wireless Messenger, NXP Semiconductors LH7952x
		ARM740T	Like ARM7TDMI, cache	MPU
	ARMv5TEJ	ARM7EJ-S	5-stage conveyor, Thumb, Jazelle DBX, advanced DSP commands	none
StrongARM	ARMv4	SA-110		16 KB/16 KB, MMU	203 MHz 1.0 DMIPS/MHz	Apple Newton 2x00 series, Acorn Risc PC, Rebel/Corel Netwinder, Chalice CATS
		SA-1100		16 KB/8 KB, MMU	203 MHz	Psion netBook
		SA-1110	Like SA-110, integrated SoC	16 KB/8 KB, MMU	206 MHz	LART (computer), Intel Assabet, Ipaq H36x0, Balloon2, Zaurus SL-5x00, HP Jornada 7xx, Jornada 560 series, Palm Zire 31
ARM8	ARMv4	ARM810	5-stage pipeline, static branch prediction, double-bandwidth memory	8 KB unified, MMU	84 MIPS @ 72 MHz 1.16 DMIPS/MHz	Acorn Risc PC prototype CPU card
ARM9TDMI	ARMv4T	ARM9TDMI	5-stage conveyor, Thumb	none
		ARM920T	Like ARM9TDMI, cache	16 KB/16 KB, MMU with FCSE (Fast Context Switch Extension)	200 MIPS @ 180 MHz	Armadillo, Atmel AT91SAM9, GP32, GP2X (first core), Tapwave Zodiac (Motorola i. MX1), Hewlett Packard HP-49/50 Calculators, Sun SPOT, Cirrus Logic EP9302, EP9307, EP9312, EP9315, Samsung S3C2442 (HTC TyTN, FIC Neo FreeRunner ), Samsung S3C2410 (TomTom navigation devices)
		ARM922T	Like ARM9TDMI, cache	8 KB/8 KB, MMU		NXP Semiconductors LH7A40x
		ARM940T	Like ARM9TDMI, cache	4 KB/4 KB, MPU		GP2X (second core), Meizu M6 Mini Player
ARM9E	ARMv5TE	ARM946E-S	Thumb, Enhanced DSP instructions, caches	variable, tightly coupled memories, MPU		Nintendo DS, Nokia N-Gage, Canon PowerShot A470, Canon EOS 5D Mark II, Conexant 802.11 chips, Samsung S5L2010
		ARM966E-S	Thumb, Enhanced DSP instructions	no cache, TCMs		STM STR91xF, includes Ethernet
		ARM968E-S	Like ARM966E-S	no cache, TCMs		NXP Semiconductors LPC2900
	ARMv5TEJ	ARM926EJ-S	Thumb, Jazelle DBX, Enhanced DSP instructions	variable, TCMs, MMU	220 MIPS @ 200 MHz,	Mobile phones: Sony Ericsson (K, W series); Siemens and Benq (x65 series and newer); LG Arena, LG Cookie Fresh; TI OMAP1710... OMAP1612, OMAP-L137, OMAP-L138; Qualcomm MSM6100...MSM6800; Freescale i.MX21, i.MX27, Atmel AT91SAM9, NXP Semiconductors LPC3000, GPH Wiz, NEC C10046F5-211-PN2-A SoC - undocumented core in the ATi Hollywood graphics chip used in the Wii, Samsung S3C2412 used in Squeezebox Duet"s Controller. Squeezebox Radio; NeoMagic MiMagic Family MM6, MM6+, MTV; Buffalo TeraStation Live (NAS); Telechips TCC7801; ZiiLABS" ZMS-05 system on a chip; Western Digital MyBook I World Edition
	ARMv5TE	ARM996HS	Clockless processor like ARM966E-S	no caches, TCMs, MPU
ARM10E	ARMv5TE	ARM1020E	6-stage pipeline, Thumb, advanced DSP instructions, (VFP)	32 KB/32 KB, MMU
		ARM1022E	Like ARM1020E	16 KB/16 KB, MMU
	ARMv5TEJ	ARM1026EJ-S	Thumb, Jazelle DBX, Enhanced DSP instructions, (VFP)	variable, MMU or MPU		Western Digital MyBook II World Edition;Conexant so4610 and so4615 ADSL SoC
XScale	ARMv5TE	80200/IOP310/IOP315	I/O Processor, Thumb, Enhanced DSP instructions
		80219			400/600 MHz	Thecus N2100 Intel 80219 processor includes a high-speed 32-bit XScale core at 400 or 600 MHz with a 64-bit PCI-X interface PCI/PCI-X bus allows you to connect Gigabit Ethernet controllers
		IOP321			600 BogoMips @ 600 MHz	Iyonix
		IOP33x
		IOP34x	1-2 core, RAID Acceleration	32K/32K L1, 512K L2, MMU
		PXA210/PXA250	Applications processor, 7-stage pipeline		PXA210: 133 and 200 MHz, PXA250: 200, 300, and 400 MHz	Zaurus SL-5600, iPAQ H3900, Sony CLIÉ NX60, NX70V, NZ90
		PXA255		32KB/32KB, MMU	400 BogoMips @ 400 MHz; 371-533 MIPS @ 400 MHz	Gumstix basix & connex, Palm Tungsten E2, Zaurus SL-C860, Mentor Ranger & Stryder, iRex ILiad
		PXA263			200, 300 and 400 MHz	Sony CLIÉ NX73V, NX80V
		PXA26x			default 400 MHz, up to 624 MHz	Palm Tungsten T3
		PXA27x	Applications processor	32 KB/32 KB, MMU	800 MIPS @ 624 MHz	Gumstix verdex, “Trizeps-Modules” PXA270 COM, HTC Universal, hx4700, Zaurus SL-C1000, 3000, 3100, 3200, Dell Axim x30, x50, and x51 series, Motorola Q, Balloon3, Trolltech Greenphone, Palm TX, Motorola Ezx Platform A728, A780, A910, A1200, E680, E680i, E680g, E690, E895, Rokr E2, Rokr E6, Fujitsu Siemens LOOX N560, Toshiba Portégé G500, Toshiba Portégé G900, Trēo 650-755p, Zipit Z2, HP i Paq 614c Business Navigator
		PXA800(E)F
		PXA3XX (codenamed "Monahans")	PXA31x has a hardware graphics accelerator	32KB/32KB L1, TCM, MMU	800 MIPS @ 624 MHz	Highscreen alex
		PXA900				Blackberry 8700, Blackberry Pearl (8100)
		IXC1100	Control Plane Processor
		IXP2400/IXP2800
		IXP2850
		IXP2325/IXP2350
		IXP42x				NSLU2 IXP460/IXP465
ARM11	ARMv6	ARM1136J(F)-S	8-stage pipeline, SIMD, Thumb, Jazelle DBX, (VFP), improved DSP instructions	variable, MMU	740 @ 532-665 MHz (i.MX31 SoC), 400-528 MHz	TI OMAP2420 (Nokia E90, Nokia N93, Nokia N95, Nokia N82), Zune, BUGbase, Nokia N800, Nokia N810, Qualcomm MSM7200 (with integrated ARM926EJ-S Coprocessor@274 MHz, used in Eten Glofiish, HTC TyTN II, HTC Nike ), Freescale i.MX31 (used in the original Zune 30gb and Toshiba Gigabeat S), Freescale MXC300-30 (Nokia E63, Nokia E71, Nokia E72, Nokia 5800, Nokia E51, Nokia 6700 Classic, Nokia 6120 Classic, Nokia 6210 Navigator , Nokia 6220 Classic, Nokia 6290, Nokia 6710 Navigator, Nokia 6720 Classic, Nokia E75, Nokia N97, Nokia N81), Qualcomm MSM7201A as seen in the HTC Dream, HTC Magic, Motorola ZN5, Motorola E8, Motorola VE66, Motorola Z6, HTC Hero, & Samsung SGH-i627 (Propel Pro), Qualcomm MSM7227 used in ZTE Link, HTC Legend, HTC Wildfire S, LG P500, LG GT540,
	ARMv6T2	ARM1156T2(F)-S	9-stage pipeline, SIMD, Thumb-2, (VFP), improved DSP instructions	variable, MPU
	ARMv6KZ	ARM1176JZ(F)-S	Like ARM1136EJ(F)-S	variable, MMU+TrustZone		Apple iPhone (original and 3G), Apple iPod touch (1st and 2nd Generation), Conexant CX2427X, Motorola RIZR Z8, Motorola RIZR Z10, NVIDIA GoForce 6100; Mediatek MT6573; Telechips TCC9101, TCC9201, TCC8900, Fujitsu MB86H60, Samsung S3C6410 (e.g. Samsung Moment), S3C6430
	ARMv6K	ARM11 MPCore	Like ARM1136EJ(F)-S, 1-4 core SMP	variable, MMU		Nvidia APX 2500
Kernel family	Architecture version	Core	Functions	Cache (I/D)/MMU	Typical MIPS @ MHz	Applications
Cortex	ARMv7-A	Cortex-A5	VFP, NEON, Jazelle RCT and DBX, Thumb-2, 8-stage conveyor, In-order, 1-4 core SMP	variable (L1), MMU+TrustZone	up to 1500 (1.5 DMIPS/MHz)	"Sparrow" (ARM code name)
		Cortex-A8	VFP, NEON, Jazelle RCT, Thumb-2; 13-stage conveyor, In-order, 2 decoders	variable (L1+L2), MMU+TrustZone	up to 2000 (2.0 DMIPS/MHz in speed from 600 MHz to greater than 1 GHz)	TI OMAP3xxx series, SBM7000, Oregon State University OSWALD, Gumstix Overo Earth, Pandora, Apple iPhone 3GS, Apple iPod touch (3rd Generation), Apple iPad (Apple A4 processor), Apple iPhone 4 (Apple A4 processor), Archos 5, Archos 101, FreeScale i.MX51-SOC, BeagleBoard, Motorola Droid, Motorola Droid X, Palm Pre, Samsung Omnia HD, Samsung Wave S8500, Nexus S, Sony Ericsson Satio, Touch Book, Nokia N900, Meizu M9, ZiiLABS ZMS-08 system on a chip, Boxchip A13
		Cortex-A9	Application profile, (VFP), (NEON), Jazelle RCT and DBX, Thumb-2, Out-of-order speculative issue superscalar (2 decoders); 9-12 conveyor stages	MMU+TrustZone	2.5 DMIPS/MHz	Apple iPhone 4S, Apple iPad 2 (Apple A5), MediaTek MT6575/6515M
		Cortex-A9 MPCore	Like Cortex-A9, 1-4 core SMP	MMU+TrustZone	10,000 DMIPS @ 2 GHz on Performance Optimized TSMC 40G (quad core?) (2.5 DMIPS/MHz per core)	PlayStation® Vita, TI OMAP4430/4440, ST-Ericsson U8500, Nvidia Tegra2, Samsung Exynos 4210, MediaTek MT6577/6517
		Cortex-A15 MPCore	1-32 core SMP; Out-of-order superscalar (3 decoders); 15+ conveyor stages; VFPv4, NEON	MMU, LPAE	3.5 DMIPS/MHz/Core; 1.0GHz - 2.5GHz (@ 28nm)
		Cortex-A7 MPCore	FPU,NEON; In-order (1 decoder); 8 conveyor stages.	MMU, LPAE	1.9 DMIPS/MHz/CPU; 0.8-1.5 GHz (@28nm)	(Broadcom, Freescale, HiSilicon, LG, Samsung, STEricsson, TexasInstruments, MediaTek)
	ARMv7-R	Cortex-R4(F)	Embedded profile, Thumb-2, (FPU)	variable cache, MPU optional	600 DMIPS @ 475 MHz	Broadcom is a user, TI TMS570
	ARMv7-ME	Cortex-M4 (codenamed "Merlin")	Microcontroller profile, both Thumb and Thumb-2, FPU. Hardware MAC, SIMD and divide instructions	MPU optional	1.25 DMIPS/MHz	NXP Semiconductors
	ARMv7-M	Cortex-M3	Microcontroller profile, Thumb-2 only. Hardware divide instructions	no cache, MPU optional	125 DMIPS @ 100 MHz	Stellaris, STM STM32, NXP LPC1700, Toshiba TMPM330FDFG, Ember's EM3xx Series, Atmel AT91SAM3, Europe Technologies EasyBCU, Energy Micro's EFM32, Actel's SmartFusion, Milander 1986BE91T
	ARMv6-M	Cortex-M0 (codenamed "Swift")	Microcontroller profile, Thumb-2 subset (16-bit Thumb instructions & BL, MRS, MSR, ISB, DSB, and DMB)	No cache	0.9 DMIPS/MHz	NXP Semiconductors NXP LPC1100, Triad Semiconductor, Melfas, Chungbuk Technopark, Nuvoton, austriamicrosystems, Milandr K1986BE2T
		Cortex-M1	FPGA targeted, Microcontroller profile, Thumb-2 subset (16-bit Thumb instructions & BL, MRS, MSR, ISB, DSB, and DMB)	None, tightly coupled memory optional	Up to 136 DMIPS @ 170 MHz (0.8 DMIPS/MHz, MHz achievable FPGA-dependent)	Actel ProASIC3, ProASIC3L, IGLOO and Fusion PSC devices, Altera Cyclone III, other FPGA products are also supported e.g. Synplicity
Kernel family	Architecture version	Core	Functions	Cache (I/D)/MMU	Typical MIPS @ MHz	Applications

Architecture

There has long been an ARM architecture reference manual that delineates all the types of interfaces that ARM supports, since the implementation details of each processor type may differ. The architecture has evolved over time, and starting with ARMv7, 3 profiles have been defined: ‘A’(application) - applications, ‘R’ (real time) - real time, ‘M’ (microcontroller) - microcontroller.

Profiles can support fewer commands (commands of a specific type).

Modes

The processor may be in one of the following operating modes:

• User mode - normal program execution mode. Most programs run in this mode.
• Fast Interrupt (FIQ) - fast interrupt mode (shorter response time)
• Interrupt (IRQ) - main interrupt mode.
• System mode - protected mode for use by the operating system.
• Abort mode - the mode into which the processor goes when a memory access error occurs (access to data or instructions at the prefetch stage of the pipeline).
• Supervisor mode - privileged user mode.
• Undefined mode is the mode the processor enters when attempting to execute an instruction unknown to it.

Switching the processor mode occurs when a corresponding exception occurs, or by modifying the status register.

Command set

To keep the design clean, simple and fast, the original ARM manufacturing was done without microcode, like the simpler 8-bit 6502 processor used in previous microcomputers from Acorn Computers.

ARM instruction set

The mode in which the 32-bit instruction set is executed.

Thumb command set

To improve code density, processors starting with ARM7TDMI are equipped with a “thumb” mode. In this mode, the processor executes an alternative set of 16-bit instructions. Most of these 16-bit instructions are translated into normal ARM instructions. Reducing instruction length is achieved by hiding some operands and limiting addressing capabilities compared to ARM's full instruction set mode.

In Thumb mode, smaller opcodes have less functionality. For example, only branches can be conditional, and many opcodes are limited to accessing only half of the processor's main registers. Shorter opcodes generally result in greater code density, although some operations require additional instructions. In situations where the memory port or bus width is limited to 16 bits, the shorter Thumb mode opcodes become much more performant compared to conventional 32-bit ARM code, since less program code will have to be loaded into the processor with limited memory bandwidth.

Hardware like the Game Boy Advance typically has a small amount of RAM available with a full 32-bit data path. But most operations are performed over a 16-bit or narrower data channel. In this case, it makes sense to use thumb code and manually optimize some of the heavy code sections using switching to full 32-bit ARM instructions.

The first processor with a thumb decoder was ARM7TDMI. All ARM9 family processors, as well as XScale, had a built-in thumb command decoder.

Thumb-2 command set

Thumb-2 is a technology that started with the ARM1156 core, announced in 2003. It extends the limited 16-bit Thumb instruction set with additional 32-bit instructions to give the instruction set additional width. Thumb-2's goal is to achieve Thumb-like code density and 32-bit ARM instruction set performance. We can say that in ARMv7 this goal was achieved.

Thumb-2 extends both ARM and Thumb instructions with even more instructions, including bitfield control, table branching, conditional execution. The new Unified Assembly Language (UAL) supports generating commands for both ARM and Thumb from the same source code. ARMv7 versions of Thumb look like ARM code. This requires caution and the use of the new if-then command, which supports execution of up to 4 consecutive test state commands. It is ignored during compilation into ARM code, but during compilation into Thumb-2 code it generates commands. For example:

; if (r0 == r1) CMP r0, r1 ITE EQ ; ARM: no code ... Thumb: IT instruction; then r0 = r2; MOVEQ r0, r2 ; ARM: conditional; Thumb: condition via ITE "T" (then); else r0 = r3; MOVNE r0, r3 ; ARM: conditional; Thumb: condition via ITE "E" (else) ; recall that the Thumb MOV instruction has no bits to encode "EQ" or "NE"

All ARMv7 chips support the Thumb-2 instruction set, and some chips, like the Cortex-m3, only support Thumb-2. The remaining Cortex and ARM11 chips support both Thumb-2 and ARM instruction sets.

Jazelle command set

Security extensions

Security extensions marketed as TrustZone Technology are found in ARMv6KZ and other later application-specific architectures. It provides a low-cost alternative to adding a dedicated security kernel by providing 2 virtual processors backed by hardware access control. This allows the application core to switch between two states called "worlds" (to avoid confusion with the names of possible domains) to prevent information from leaking from a more important world to a less important one. This world switch is usually orthogonal to all other processor capabilities. This way, each world can run independently of other worlds using the same core. Memory and peripherals are respectively designed to fit the kernel world, and can use this to gain access control to kernel secrets and codes. Typical TrustZone Technology applications should run a full operating system in the less critical world, and compact, security-specific code in the more critical world, allowing Digital Rights Management to much more accurately control media usage on ARM-based devices, and preventing unauthorized access to the device .

In practice, since the specific implementation details of TrustZone remain proprietary and are not disclosed, it remains unclear what level of security is guaranteed for a given threat model.

Debugging

All modern ARM processors include hardware debugging tools, since without them software debuggers would not be able to perform the most basic operations such as stopping, indenting, setting breakpoints after a reboot.

The ARMv7 architecture defines basic debugging capabilities at the architectural level. These include breakpoints, watchpoints, and running commands in debug mode. Such tools were also available with the EmbeddedICE debug module. Both modes are supported - stop and review. The actual transport mechanism that is used to access debugging facilities is not architecturally specified, but the implementation typically includes JTAG support.

There is a separate "kernel view" debugging architecture that is not architecturally required by ARMv7 processors.

Registers

ARM provides 31 general purpose registers with a width of 32 bits. Depending on the mode and state of the processor, the user has access only to a strictly defined set of registers. In ARM state, 17 registers are constantly available to the developer:

• 13 general purpose registers (r0..r12).
• Stack Pointer (r13) - contains the stack pointer of the executing program.
• Link register (r14) - contains the return address in branch instructions.
• Program Counter (r15) - bits contain the address of the instruction being executed.
• Current Program Status Register (CPSR) - contains flags that describe the current state of the processor. Modified when executing many instructions: logical, arithmetic, etc.

In all modes except User mode and System mode, the Saved Program Status Register (SPSR) is also available. After an exception occurs, the CPSR register is stored in SPSR. This fixes the state of the processor (mode, state; flags of arithmetic, logical operations, interrupt enable) at the moment immediately before the interruption.

usr	sys	svc	abt	und	irq	fiq
R0
R1
R2
R3
R4
R5
R6
R7
R8						R8_fiq
R9						R9_fiq
R10						R10_fiq
R11						R11_fiq
R12						R12_fiq
R13		R13_svc	R13_abt	R13_und	R13_irq	R13_fiq
R14		R14_svc	R14_abt	R14_und	R14_irq	R14_fiq
R15
CPSR
		SPSR_svc	SPSR_abt	SPSR_und	SPSR_irq	SPSR_fiq

Working with memory

Supported I/O systems

Most existing microprocessor models implement a PCI bus and the ability to work with external dynamic random access memory (DRAM). Processors designed for consumer devices also usually integrate: USB bus controllers, IIC bus controllers, an AC’97-compatible audio device, a device for working with SD and MMC flash media, and a serial port controller.

All processors have general purpose input/output (GPIO) lines. In consumer devices, they can be connected to “quick launch” buttons, signal LEDs, a scroll wheel (JogDial), and a keyboard.

The process of launching the OS on ARM machines

Support on Unix-like systems

The ARM architecture is supported by Unix and Unix-like operating systems GNU/Linux, BSD, QNX, Plan 9, Inferno, Solaris, Mac OS X, iOS, WebOS and Android.

Linux

The following distributions support ARM processors:

BSD

The following BSD derivatives support ARM processors:

Solaris

Support for other operating systems

Operating systems that run on ARM: ReactOS, FreeRTOS, Nucleus, Symbian OS, Windows CE, RISC OS, Windows RT.

ARM licensees and approximate license cost

ARM does not produce or sell processors based on its designs, but it does license processors to interested partners. ARM offers a wide range of licensing terms that vary in cost and detail. For all license holders, ARM supplies a description of the kernel hardware, as well as a complete set of software development tools (compiler, debugger), as well as the right to sell manufactured ARM processors. Some customers manufacture processors for third parties.

ARM's 2006 annual report reported $161 million in revenue from licensing 2.5 billion units (processors). This is equivalent to $0.067 per unit. However, this is a very average figure - after all, this includes licenses for very expensive new processors and old cheap processors.

Notes

1. "ARMed for the living room".
2. "An interview with Steve Furber"
3. Samsung Nexus 10 - Geekbench Browser
4. MacBook Air - Geekbench Browser
5. Apache Benchmarks for Calxeda's 5-Watt Web Server – ARM Servers, Now!
6. http://www.apm.com/global/x-gene/docs/2012_03_OPP%20Cloudy%20with%20a%20Chance%20of%20ARM.pdf
7. “ARM810 - Dancing to the Beat of a Different Drum” ARM Holdings presentation at Hot Chips 1996-08-07.
8. Register 13, FCSE PID register ARM920T Technical Reference Manual
9. Neo1973: GTA01Bv4 versus GTA02 comparison. Archived from the original on March 13, 2012. Retrieved November 15, 2007.
10. S3C2410. Archived from the original on March 13, 2012. Retrieved January 13, 2010.
11. Rockbox Samsung SA58xxx series. Archived
12. Rockbox Meizu M6 Port – Hardware Information. Archived from the original on March 13, 2012. Retrieved February 22, 2008.
13. Datasheets - Magic Lantern Firmware Wiki
14. STR9 – STR912 – STR912FW44 microcontroller – documents and files download page. mcu.st.com. (inaccessible link - story) Retrieved April 18, 2009.
15. Starlet
16. Benchmarks - Albatross. Albatross-uav.org (18 June 2005). (inaccessible link - story) Retrieved April 18, 2009.
17. ARM1136J(F)-S – ARM Processor. Arm.com. Archived
18. Qualcomm chips kernel ARM - from phones to laptops. xi0.info. Archived
19. Qualcomm MSM7227 RISC Chipset. pdadb.net. Archived from the original on March 13, 2012. Retrieved May 8, 2010.
20. GoForce 6100. Nvidia.com. Archived from the original on March 13, 2012. Retrieved April 18, 2009.
21. Mediatek MT6573. http://www.mediatek.com. ; Archived from the original on June 6, 2012. Retrieved April 18, 2009.
22. Samsung S3C6410 and S3C6430 Series ARM Processors. Samsung. Retrieved October 8, 2009., and the Qualcomm MSM7627 as seen in the Palm Pixi and Motorola Calgary/Devour
23. Merritt, Rick"ARM stretches out with A5 core, graphics, FPGAs". EE Times (21 October 2009). Archived from the original on March 13, 2012. Retrieved October 28, 2009.
24. Clarke, Peter ARM tips plans for Swift and Sparrow processor cores. EE Times (February 3, 2009). Archived from the original on March 13, 2012. Retrieved April 18, 2009.
25. Segan, Sascha ARM's Multicore Chips Aim for Netbooks. PC Magazine (April 9, 2009). Archived from the original on March 13, 2012. Retrieved April 18, 2009.
26. http://pc.watch.impress.co.jp/video/pcw/docs/423/409/p1.pdf
27. Cortex-A15 Processor - ARM
28. Cortex-A7 Processor - ARM
29. Benz, Benjamin Cortex Nachwuchs bei ARM. Heise.de (February 2, 2010). Archived from the original on March 13, 2012. Retrieved May 3, 2010.
30. Clarke, Peter ARM preps tiny core for low-power microcontrollers. EE Times (23 February 2009). Archived from the original on March 13, 2012. Retrieved November 30, 2009.
31. Walko, John NXP first to demo ARM Cortex-M0 silicon. EE Times (23 March 2009). Archived from the original on March 13, 2012. Retrieved June 29, 2009.
32. ARM Powered VCAs" Triad Semiconductor
33. Cortex-M0 used in low power touch controller - 10/06/2009 - Electronics Weekly
34. Chungbuk Technopark Chooses ARM Cortex-M0 Processor
35. Google Translate
36. Austriamicrosystems Chooses ARM Cortex-M0 Processor For Mixed Signal Applications
37. “ARM Extends Cortex Family with First Processor Optimized for FPGA”, ARM press release, March 19, 2007. Retrieved April 11, 2007.

Everyone who is interested in mobile technologies has certainly heard the name ARM. Many understand this abbreviation as a type of processor for smartphones and tablets, others clarify that this is not a processor at all, but its architecture. And certainly few people have delved into the history of the emergence of ARM. In this article we will try to understand all these nuances and tell you why modern gadgets need ARM processors.

A brief excursion into history

When you search for “ARM,” Wikipedia gives two meanings for this abbreviation: Acorn RISC Machine and Advanced RISC Machines. Let's start in order. In the 1980s, Acorn Computers was founded in the UK, which began its activities by creating personal computers. At that time, Acorn was also called the “British Apple.” A decisive period for the company came in the late 1980s, when its chief engineer took advantage of the decision of two local university graduates to come up with a new type of reduced instruction set (RISC) processor architecture. This is how the first computer based on the Acorn Risc Machine processor appeared. Success was not long in coming. In 1990, the British entered into an agreement with Apple and soon began work on a new version of the chipset. The development team eventually formed a company called Advanced RISC Machines, inspired by the processor. Chips with the new architecture also became known as Advanced Risc Machine or ARM for short.

Since 1998, Advanced Risc Machine became known as ARM Limited. Currently, the company is not engaged in the production and sale of its own processors. The main and only activity of ARM Limited is the development of technologies and the sale of licenses to various companies to use the ARM architecture. Some manufacturers buy a license for ready-made cores, others buy a so-called “architectural license” to produce processors with their own cores. Among such companies are Apple, Samsung, Qualcomm, nVidia, HiSilicon and others. According to some reports, ARM Limited earns $0.067 on each such processor. This figure is average and also outdated. Every year there are more and more cores in chipsets, and new multi-core processors outperform outdated models in cost.

Technical features of ARM chips

There are two types of modern processor architectures: CISC(Complex Instruction Set Computing) and RISC(Reduced Instruction Set Computing). The CISC architecture includes the x86 processor family (Intel and AMD), and the RISC architecture includes the ARM family. The main formal difference between RISC and CISC and, accordingly, x86 from ARM is the reduced instruction set used in RISC processors. For example, each instruction in a CISC architecture is transformed into several RISC instructions. In addition, RISC processors use fewer transistors and thus consume less power.

The main priority of ARM processors is the ratio of performance to energy consumption. ARM has a higher performance per watt ratio than x86. You can get the power you need from 24 x86 cores or from hundreds of small, low-power ARM cores. Of course, even the most powerful processor based on ARM architecture will never be comparable in power to an Intel Core i7. But the same Intel Core i7 needs an active cooling system and will never fit into a phone case. Here ARM has no competition. On the one hand, this looks like an attractive option for building a supercomputer using a million ARM processors instead of a thousand x86 processors. On the other hand, the two architectures cannot be compared unambiguously. In some ways, ARM will have an advantage, and in others, x86 will have an advantage.

However, calling ARM architecture chips processors is not entirely correct. In addition to several processor cores, they also include other components. The most appropriate term would be “single chip” or “system on a chip” (SoC). Modern single-chip systems for mobile devices include a RAM controller, graphics accelerator, video decoder, audio codec and wireless communication modules. As mentioned earlier, individual chipset components may be developed by third-party manufacturers. The most striking example of this is the graphics cores, which, in addition to ARM Limited (Mali graphics), are developed by Qualcomm (Adreno), NVIDIA (GeForce ULP) and Imagination Technologies (PowerVR).

In practice it looks like this. Most budget Android mobile devices come with chipsets manufactured by the company MediaTek, which almost invariably follows the instructions of ARM Limited and completes them with Cortex-A cores and Mali graphics (less often PowerVR).

A-brands often use manufactured chipsets for their flagship devices Qualcomm. By the way, the latest Qualcomm Snapdragon chips (,) are equipped with completely custom Kryo cores for the central processor and Adreno for the graphics accelerator.

Concerning Apple, then for the iPhone and iPad the company uses its own A-series chips with the PowerVR graphics accelerator, which are produced by third-party companies. Thus, it has a 64-bit quad-core A10 Fusion processor and a PowerVR GT7600 graphics processor.

The architecture of the family of processors is considered relevant at the time of writing ARMv8. It was the first to use a 64-bit instruction set and support for more than 4 GB of RAM. The ARMv8 architecture is backward compatible with 32-bit applications. The most efficient and most powerful processor core developed by ARM Limited is currently Cortex-A73, and most SoC manufacturers use it unchanged.

Cortex-A73 provides 30% higher performance than Cortex-A72 and supports the full range of ARMv8 architecture. The maximum processor core frequency is 2.8 GHz.

Scope of use of ARM

ARM's greatest fame came from the development of mobile devices. On the eve of mass production of smartphones and other portable equipment, energy-efficient processors came in handy. The development of ARM Limited culminated in 2007, when the British company renewed its partnership with Apple, and some time later the Cupertino team presented its first iPhone with a processor based on ARM architecture. Subsequently, a single-chip system based on ARM architecture became an unchanged component of almost all smartphones on the market.

ARM Limited's portfolio is not limited only to cores of the Cortex-A family. In fact, there are three series of processor cores under the Cortex brand, which are designated by the letters A, R, M. Core family Cortex-A, as we already know, is the most powerful. They are mainly used in smartphones, tablets, TV set-top boxes, satellite receivers, automotive systems, and robotics. Processor cores Cortex-R optimized for performing high-performance tasks in real time, so such chips are found in medical equipment, autonomous security systems, and storage media. The main task of the family Cortex-M is simplicity and low cost. Technically, these are the weakest processor cores with the lowest power consumption. Processors based on such cores are used almost everywhere where minimal power and low cost are required from a device: sensors, controllers, alarms, displays, smart watches and other equipment.

In general, most modern devices from small to large that require a CPU use ARM chips. A huge plus is the fact that the ARM architecture is supported by many operating systems on the Linux platform (including Android and Chrome OS), iOS, and Windows (Windows Phone).

Market competition and future prospects

It is worth recognizing that at the moment ARM has no serious competitors. And, by and large, this is due to the fact that ARM Limited made the right choice at a certain time. But at the very beginning of its journey, the company produced processors for PCs and even tried to compete with Intel. After ARM Limited changed the direction of its activities, it also had a difficult time. Then the software monopolist represented by Microsoft, having entered into a partnership agreement with Intel, left no chance for other manufacturers, including ARM Limited - Windows OS simply did not work on systems with ARM processors. No matter how paradoxical it may sound, but now the situation can change dramatically, and Windows OS is ready to support processors on this architecture.

In the wake of the success of ARM chips, Intel attempted to create a competitive processor and entered the market with a chip Intel Atom. It took her much longer to do this than ARM Limited. The chipset entered production in 2011, but, as they say, the train has already left. Intel Atom is a CISC processor with x86 architecture. The company's engineers have achieved lower power consumption than in ARM, but at the moment a variety of mobile software has poor adaptation to the x86 architecture.

Last year, Intel abandoned several key decisions in the further development of mobile systems. Essentially a company for mobile devices as they became unprofitable. The only major manufacturer that equipped its smartphones with Intel Atom chipsets was ASUS. However, Intel Atom still received widespread use in netbooks, nettops and other portable devices.

ARM Limited's position in the market is unique. At the moment, almost all manufacturers use its developments. However, the company does not have its own factories. This does not prevent it from standing on a par with Intel and AMD. The history of ARM includes another interesting fact. It is possible that now ARM technology could belong to Apple, which was at the heart of the formation of ARM Limited. Ironically, in 1998, the Cupertino residents, experiencing times of crisis, sold their share. Now Apple is forced, along with other companies, to buy a license for the ARM processors used in the iPhone and iPad.

Nowadays, ARM processors are capable of performing serious tasks. In the near future, they will be used in servers; in particular, the data centers of Facebook and PayPal already have such solutions. In the era of the development of the Internet of Things (IoT) and smart home devices, ARM chips have become even more in demand. So the most interesting things are yet to come for ARM.