International Journal of Electronic Engineering and Computer Science Vol. 3, No. 2, 2018, pp. 29-38 http://www.aiscience.org/journal/ijeecs ARM Processor Architecture: An Emerging Architecture in Smart Phones Naseer Ahmad, Muhammad Waqas Boota * Department of Computer Science, Virtual University of Pakistan, Lahore, Pakistan Abstract ARM is a 32-bit RISC processor architecture. It is develop and licenses by British company ARM holdings. ARM holding does not manufacture and sell the CPU devices. ARM holding only licenses the processor architecture to interested parties. There are two main types of licences implementation licenses and architecture licenses. ARM processors have a unique combination of feature such as ARM core is very simple as compare to general purpose processors. ARM chip has several peripheral controller, a digital signal processor and ARM core. ARM processor consumes less power but provide the high performance. Now a day, ARM Cortex series is very popular in Smartphone devices. We will also see the important characteristics of cortex series. We discuss the ARM processor and system on a chip (SOC) which includes the Qualcomm, Snapdragon, nVidia Tegra, and Apple system on chips. In this paper, we discuss the features of ARM processor and Intel atom processor and see which processor is best. Finally, we will discuss the future of ARM processor in Smartphone devices. Keywords RISC, ISA, ARM Core, System on a Chip (SoC) Received: May 6, 2018 / Accepted: June 15, 2018 / Published online: July 26, 2018 @ 2018 The Authors. Published by American Institute of Science. This Open Access article is under the CC BY license. http://creativecommons.org/licenses/by/4.0/ ability to shutdown the clock automatically that’s why it is 1. Introduction very popular in embedded applications. [2] ARM is a 32 bit RISC processor. ARM processor is designed ARM holding does not manufacture the electronic chips but and licensed by British company ARM holding. It is develop only provide the licenses and design to other semiconductor in 1980’s by Acorn Computers Ltd. Its old name was an manufactures. ARM processor and system on chip (SoC) acronym for Acorn RISC Machine. Now its new name is an include the QualComm, Snapdragon, nVidia Tegra, and Advanced RISC Machine. In 2013 ARM is a mostly widely Apple system on chip. ARM offers the different licensing used 32-bit instruction set architecture. In 2010 ARM terms which are varying in cost. [7] processors reported the shipments of 6.1 billion, represents ARM provides the complete software development toolkit the 95% of smart phone, 35% of digital televisions and 10% and sells the Silicon containing chip the ARM CPU. There of mobile computers. are two main types of licenses implementation licenses and Design of ARM processor is very simple and covers very less architecture licenses integrated circuit containing an ARM space as compare to powerful RISC machine. ARM’s goal is processor core, while the architecture licenses develop their to optimize the price and performance ratio rather than own processor with ARM ISA. building the most powerful processor in the market. ARM processor has a unique combination of features which Assembling of ARM processor takes a very less time. As we makes the ARM processor very popular in embedded know that chip is very small and CMOS technology make architecture. ARM processor core is very simple as compare this processor energy efficient. ARM processors have the to general purpose processors. ARM uses a very less number * Corresponding author E-mail address: International Journal of Electronic Engineering and Computer Science Vol. 3, No. 2, 2018, pp. 29-38 30 of transistors. ARM chip can contain several peripheral Therefore Acorn engineers decided to design their own controllers, digital signal processor, very little memory on microprocessor. After two years, the Berkeley RISC 1 project chip and ARM core. builds a very simple microprocessor. Acorn decided to pick ISA and pipeline are used to minimize the energy which is up this Berkeley approach and launch their 26 bit Acorn RISC Machine in 1985. The first ARM processor is called as requiring in mobile embedded systems. ARM processor has a load and store ISA. Most of the processors use a 3-stage the ARM version 1 architecture. In 1992 a new, ARM pipeline consisting of fetch, decode and execution stages. included the coprocessor support feature. The pipeline executes one instruction per cycle. Later, ARM v2 architecture included the on-chip cache in The ARM processor designs are using custom standard cells. ARM3 processor. In 1990 Apple decided to use the ARM processor in Newton PDA. A joint venture by Acorn and The ARM architecture is a modular, the main important Apple to design a new processor; now, the new name is the component of an ARM processor is an integer pipeline while ARM, which stands for Advanced RISC machine. Third the other components caches, MMU, floating point and coprocessors are optional. version of ARM architecture was consisting of 32 bit addressing; MMU and 64 bit multiply accumulate Thumb mode uses a 16 bit instruction to reduce the code instructions. The release of ARM 6 and ARM 7 processors density. This increase the performance of the processor and Newton PDA moved to the embedded market. where In 1996 ARM cores v4 was support for Thumb 16-bit smaller memory and data buses are used. Some new compressed instruction set. Thumb code takes 40% less processors allow Java byte code execution directly from space compared to regular 32-bit while ARM code is a little ARM pipeline called Jazelle. less efficient. The most popular ARM cores v4 is the ARM can extend the instruction set when coprocessor is ARM7TDMI core, which is the most popular ARM product. added. [2] This is used in most Apple iPod players, including the video iPod. In the end we compare the features of ARM and Intel atom processors. We also see the 64-bit ARM processor and the In 1999, ARM v5 architecture introduced digital signal future of ARM processor. [11] processing and Java byte code extensions to the ARM instruction set. The most popular implementation of this architecture is the Intel X-Scale processor. 2. REVIEW and Related Work The 6th generation of the ARM architecture released in 2001, The ARM started his work in 1983 when a company Acorn which introduce SIMD instruction set extension, improved computer was searching a 16 bit microprocessor for their Thumb instruction set, the Trust Zone virtualisation next desktop machine. Early microprocessors did not cover technology, and multiprocessor support. their requirements. These parts are slower than standard parts The newly released ARMv7 architecture extended SIMD available at that time. At that time CISC was taking hundred instructions set and improved floating point support. [2] of cycles to execute. Table 1. The history of ARM Processor. Version Features Implementations v1 The first commercial RISC (26-bit) ARM 1 v2 Coprocessor support ARM 2, ARM 3 v3 32-bit, MMU, 64-bit MAC ARM 6, ARM 7 ARM7TDMI, ARM8, v4 Thumb ARM9TDMI, Strong ARM v5 DSP and Jazelle extensions ARM10, XScale v6 SIMD, Thumb-2, Trust-Zone, multiprocessing ARM11, ARM11 MPCore all major operating systems such as Symbian OS, Palm OS, 3. World of ARM LINUX and Windows CE. ARM also provides the software solutions to existing market segments. ARM lies at the heart of digital products, mobile phone, These benefits are making ARM company a complete digital camera and automotive system. ARM is a leading solution provider. There are above the forty parterres which intellectual property (IP) of high performance, low cost, use the ARM licences. ARM enables original equipment power efficient and system on chip (SOC) designs with the manufacturers (OEM) which recognize accelerated time to different organizations. ARM architecture is compatible with 31 Naseer Ahmad and Muhammad Waqas Boota: ARM Processor Architecture: An Emerging Architecture in Smart Phones market through complete product offerings. These are Prime 2. In Booth multiplexer, the multiplexer has three 32 bits Cell Peripherals, embedded software IP, development tools, inputs. While, all the inputs come from the register file. training, and support. So, the output of multiplier is only the 32 least significant ARM's Global Technology Partner Network is the largest in bits of the product. This multiplication starts when we start the input goes active. the industry, spanning from semiconductor manufacturers to distributors. 3. In Barrel shifter, the Barrel shifter shifts the 32 bit input. ARM ensure that the partnership provide the solutions in real This input comes from the register file. This is may be the time operating systems, development systems, application immediate data. The shifter have other control inputs software and design consulting. [5] which comes from the instruction register (IR). While, the shift field in the instruction can control the operation of Barrel shifter. This field represents the type of shift which 4. Design of ARM Architecture is to be performed. The possible type of shift is logical left or right, arithmetic right or rotates right. The design of ARM processor architecture pass through many steps until it reaches the final form. The ARM 4. In control unit, control unit is the heart of microprocessor. processor is constructed from the following components This is responsible for the system operation. So, control Arithmetic Logic Unit, Booth multiplier, Barrel shifter and unit is a pure combinational circuit. In our design, control control unit. We will discuss these components: unit is implemented by simple state machine. The processor timing is also included in the control unit. 1. In ALU, the ALU has two 32 bit inputs. The first input Signals from the control unit are connected to every comes from the register file and second input comes from component in the processor to supervise its operation.