This article will completely focus on the ARM Processor Architecture and its Features. One of the most widely used and licensed CPU cores worldwide is the Advanced RISC Machine (ARM) microcontroller.
In 1978, Cambridge University created the first ARM processor, and in 1985, the Acorn Group of Computers created the first ARM RISC CPU. Because of their advantages—such as their low power consumption and reasonable performance—these processors are particularly utilised in portable devices like digital cameras, cell phones, wireless communication technologies, home networking modules, and other embedded systems. An outline of the ARM architecture is provided in this article, along with the operating principles of each module.
Also learn: Instruction Set Architecture of 8085 Microprocessor
ARM Processor Architecture and its Features
In Arm Processor Architecture, the RISC (Reduced Instruction Set Computing) architecture serves as the foundation for the ARM (Advanced RISC Machine) series of CPUs. ARM processors, which were first created by Acorn Computers in the 1980s, are currently designed by Arm Holdings and extensively licensed for usage in chips by various businesses, including Apple, Qualcomm, Samsung, and others.
It is a popular computer chip that is well-known for its effectiveness and adaptability. These processors, which were created by ARM Limited using a simplified RISC architecture, are licensed to different businesses instead of being produced in-house.
In the ARM Processor Architecture, Tech businesses may create and modify processors for a wide range of devices, including PCs, smartphones, tablets, and smart devices, thanks to ARM’s distinctive business model. They are the go-to option for mobile computing because of their remarkable balance between processing power and energy economy, which allows for extended battery life without sacrificing performance.
Common ARM Processor Families
- Cortex-M Series: Specially for microcontrollers (real-time control, low power)
- Cortex-R Series: Mainly for real-time systems (e.g., robotics, automotive)
- Cortex-A Series: Basically for application processors (e.g., tablets, smartphones)
- Neoverse: For cloud computing and infrastructure
- Apple Silicon (e.g., M1, M2): Custom ARM-based processors for Macs
ARM Processor Advantages
In the ARM Processor Architecture, Below mentioned points are some of the main advantages of the ARM Processor.
- Low Power Consumption: Perfect for mobile and battery-operated devices.
- High Performance per Watt: Effective processing at low energy consumption.
- Compact and Simple Design: Lowers chip size and manufacturing costs.
- Faster execution is made possible by the RISC architecture, which simplifies instructions.
- Broad Ecosystem Support: Numerous development tools and software.
- Scalability: Found in a wide range of gadgets, including smartphones and microcontrollers.
- Economical Licensing Model: Facilitates widespread manufacturers’ adoption.
ARM Processor Dis Advantages
In the ARM Processor Architecture, Below mentioned points are some of the dis advantages of the ARM Processor.
- Compatibility with Windows computers is limited because they are unable to run x86-based software natively.
- Limited High-End Performance: In general, ARM chips perform worse than top-tier x86 CPUs.
- Needs Skilled Programming: ARM programming can be challenging and calls for developers with experience.
- Less Effective Instruction Scheduling: ARM handles instruction scheduling less effectively, which could have an impact on performance on challenging tasks.
Arm Processor Features
Multiprocessing Systems
In ARM Processor Architecture, ARM processors are made to work with multiprocessing systems, which use many processors to process data at once. The ARMv6K, the first Asymmetric Multiprocessing (AMP) processor, has integrated hardware support for up to four CPUs.
In order to provide effective multitasking and improved performance, multi-core SoCs (System on Chips) frequently use modern ARM processors, which come in single-core to octa-core (or more) configurations.
Tightly Coupled Memory
IN ARM Processor Architecture, ARM processors have tightly connected memory. The response time of this is quite quick. It can also be employed in situations when cache memory is unexpected due to its low latency (rapid reaction). TCM is perfect for real-time and safety-critical applications because it offers deterministic access times.
Memory Management
In ARM Processor Architecture, Advanced memory management components like the Memory Protection Unit (MPU) and the Memory Management Unit (MMU) are found in ARM CPUs. These systems are necessary for:
-
- Virtual memory implementation (MMU)
- Efficient memory utilization
- Enabling operating system support (e.g., Linux)
- Protecting critical sections of memory (MPU)
Thumb-2 Technology
In ARM Processor Architecture, Variable-length instruction sets are made possible by Thumb-2 Technology, which was first introduced in 2003. By supplementing the basic 16-bit Thumb instruction set with 32-bit instructions, it improves code density and execution speed. This dual-width feature provides:
-
- Decreased use of memory.
- Better than the typical 16-bit Thumb.
- Enhanced interoperability with current ARM instructions
One-Cycle Execution Time
In ARM Processor Architecture, Every instruction on the CPU is optimised for the ARM processor. Every instruction has a set duration, which provides time to get subsequent instructions before carrying out the current ones. CPI (Clock Per Instruction) is one cycle for ARM.
Pipelining
In ARM Processor Architecture, Pipelines are used to process instructions in parallel. Instructions are decoded and dissected at a single pipeline stage. The channel increases throughput (processing rate) by moving forward one step at a time.
Arm Processor Architecture
Arithmetic Logic Unit (ALU)
In ARM Processor Architecture, There are two 32-bit inputs on the ALU. The shifter provides the other, while the register file provides the primary. The flags in the status registers are altered by the ALU outputs.
Both the Count and the V-bit output are sent to the C and V flags, respectively. The ALU output procedure is carried out by NORed to obtain the Z flag, even though the foremost significant bit actually symbolises the S flag. The 4-bit function bus of the ALU allows for the implementation of up to 16 opcodes.
Booth Multiplier Factor
Three 32-bit inputs make up the multiplier factor, while the register file provides the inputs’ return. Only 32-Least Significant Bits of the product are produced by the multiplier. The block diagram above displays the multiplier factor’s entity representation. When the beginning 04 input becomes active, the multiplication begins. When the production is finished, the fin goes high.
Booth Algorithm
For numbers that are the complement of two, the Booth algorithm is a notable multiplication algorithmic rule. Both positive and negative numbers are treated equally in this way. Additionally, faster multiplication is made feasible by skipping over the runs of 0s or 1s in the multiplier factor without doing any addition or subtraction. The multiplier test bench’s simulation results are displayed in the figure. It is evident that the multiplication takes only 16 clock cycles to complete.
Barrel Shifter
The input to be moved by the barrel shifter is 32-bit. This input could come from the register file or it could be instantaneous data. The instruction register provides several control inputs to the shifter. The barrel shifter’s operation is managed by the Shift field in the instruction. This parameter specifies the type of shift that to be made (rotate right, arithmetic right, or logical left or right). The lower six bits of a register in the register file, or an immediate field in the instruction, contain the amount by which the register should be moved.
A shift of up to 32 bits is possible due to the 6-bit shift_val input bus. Shift left, shift right, an arithmetic shift right, and rotate right are indicated by the shifttype, which also shows the required shift sort of 00, 01, 10, and 11. Multiplexers are specifically used in the barrel shifter.
Control Unit
In ARM Processor Architecture, The design of the control unit is the most crucial component of the entire microprocessor since it is the central component and is in charge of system functioning.
Sometimes the circuit architecture of the control unit is purely combinational. Here, an uncomplicated state machine is used to create the control unit. The processor’s timing is also included in the control unit. Every part of the processor receives signals from the control unit to monitor its functioning.
The Benefits of ARM Architecture
In ARM Processor Architecture, The following are the factors that contribute to the ARM processor’s value to the US:
- Broad Adoption Across Devices: One of the most widely used electrical architectures worldwide is the Advanced RISC Machine (ARM) architecture. It is extensively used in embedded systems, computers, feature phones, and smartphones.
- Superior to x86 in a Lot of Ways: The server market is dominated by high-performance x86 CPUs, although ARM provides smaller, more affordable, and energy-efficient processors. It is becoming more widely accepted as a superior option for scalable and portable systems as a result of these advantages.
- Better Battery Life and Low electricity Consumption: ARM processors are perfect for battery-powered gadgets because they use less electricity to function. Longer battery life is the result, which is important for portable and mobile devices.
- Compact and Economical Design: Because ARM processors are smaller, they contribute to smaller device form factors. They are more economical for widespread use because to their RISC-based design’s simplification, which lowers production costs.
- Utilised in High-Performance Computing: Fugaku, the fastest supercomputer in the world as of 2021, is powered by ARM, which is not just found in mobile devices. This demonstrates how ARM can grow to accommodate high-performance computing (HPC).
- Flexibility for Hardware Designers: ARM gives hardware engineers greater design viability. Unlike fixed-architecture systems like x86, designers can modify CPU cores and have more control over the supply chain.
