Introduction to ARM .Architecture and history of ARM

1. ARM & ARM
ARCHITECtURE
Submitted by :-
Sneha soni
SG-19548
ECE,7th sem
Submitted to :-
Dr. Ankur Singh Kang

2. OUTLINES .
● Introduction
● Architecture
● History
● Features
● Application
● Advantage
● Disadvantages

3. INTRODUCTION
ARM stands for Advanced Risc Machine. It is one of the most licensed and
extensive processor cores in the world. In the year of 1978, first ARM
processor was introduced by Cambridge University. The first ARM processor
was produced by Acorn Group Of Computers in year 1985. ARM was founded
and became very popular in 1990. In 2007, ARM processors were used in
more than 98% of mobile phones and approximately 10 billion processors
were shipped in 2008. ARM was the latest technology which was replaced by
micro-controllers and microprocessors. In general, ARM is a 16-bit/32-bit
processor or controller. In advanced digital products, ARM acts as a heart.

5. ARM ARCHITECTURE .
The ARM architecture processor is an advanced reduced instruction set
computing [RISC] machine and it’s a 32bit reduced instruction set computer (RISC)
microcontroller. It was introduced by the Acron computer organization in 1987.
This ARM is a family of microcontroller developed by makers like ST
Microelectronics , Motorola, and so on. The ARM architecture comes with totally
different versions like ARMv1, ARMv2, etc., and, each one has its own advantage
and disadvantages.These processors are specially used in portable devices like
digital cameras, mobile phones, home network modules, wireless communication
technologies, access control, communication gateways, medical Systems and in
many other embedded systems.

7. VON NEUMANN ARCHITECTURE .
The von Neumann architecture is a computer architecture based on a 1945
description by john von neumann
The term "von Neumann architecture" has evolved to refer to any stored
program computer in which an instruction fetech and a data operation
cannot occur at the same time (since they share a common bus). This is
referred to as thevon Neumann bottelneck, which often limits the
performance of the corresponding system.[3]
The design of a von Neumann architecture machine is simpler than in a
Harvard Architecture machine—which is also a stored-program system, yet
has one dedicated set of address and data buses for reading and writing to
memory, and another set of address and data buses to fetch instruction.

8. HARVARD ARCHITECTURE .
In modified Harvard Architecture machine is very much like a Harvard architecture
machine, but it relaxes the strict separation between instruction and data while still letting
the CPU concurrently access two (or more) memory buses. The most common
modification includes separate instruction and data caches backed by a common address
space. While the CPU executes from cache, it acts as a pure Harvard machine. When
accessing backing memory, it acts like a von Neumann machine (where code can be
moved around like data, which is a powerful technique). This modification is widespread in
modern processors, such as the ARM architecture, Power ISA and x86 processors. It is
sometimes loosely called a Harvard architecture, overlooking the fact that it is actually
"modified".

9. RISC ARCHITECTURE .
The main idea behind this is to make hardware simpler by using an instruction set composed of a few basic
steps for loading, evaluating, and storing operations just like a load command will load data, a store command
will store the data.
Reduce the cycles per instruction at the cost of the number of instructions per program.
Characteristic of RISC –
1. Simpler instruction, hence simple instruction decoding.
2. Instruction comes undersize of one word.
3. Instruction takes a single clock cycle to get executed.
4. More general-purpose registers.
5. Simple Addressing Modes.
6. Fewer Data types.
7. A pipeline can be achieved.

10. CISC ARCHITECTURE .
The main idea is that a single instruction will do all loading, evaluating, and storing operations just like a
multiplication command will do stuff like loading data, evaluating, and storing it, hence it’s complex.
The CISC approach attempts to minimize the number of instructions per program but at the cost of an
increase in the number of cycles per instruction.
Characteristic of CISC –
1. Complex instruction, hence complex instruction decoding.
2. Instructions are larger than one-word size.
3. Instruction may take more than a single clock cycle to get executed.
4. Less number of general-purpose registers as operations get performed in memory itself.
5. Complex Addressing Modes.
6. More Data types.

11. HISTORY OF ARM .
The history of ARM processor dates back to 1983 in England when
Acorn Computers Ltd officially launched an Acorn RISC Management
project after being inspired to design its own processor by Berkeley
RISC, one of the high-impact projects under ARPA’s (Advanced
Research Projects Agency, now converted to DARPA) VLSI project,
dealing with RISC-based microprocessor design led by David Patterson
who coined the term ‘RISC.’ As the name suggests, it does not mean
that the processors with less than 100 instructions are qualified to
RISC category, but instead they should have an highly optimised
instruction set

12. The Arm processor was licensed to many semiconductor companies for an
upfront license fee and then royalties on production silicon. This made Arm
a partner to all these companies, effectively trying to speed up their time to
market as it benefited both Arm and its partners. For me personally, this
model was one that was never taught to us in school, and doesn’t really
show its head in the business world much, but it creates a fantastic model of
using Arm architecture in a large ecosystem – which effectively helps
everyone in the industry towards a common goal; creating and producing
cutting edge technology.

15. USER Mode: The user mode is a normal mode, which has the least number of registers. It doesn’t have
SPSR and has limited access to the CPSR.
FIQ and IRQ: The FIQ and IRQ are the two interrupt caused modes of the CPU. The FIQ is processing
interrupt and IRQ is standard interrupt. The FIQ mode has additional five banked registers to provide more
flexibility and high performance when critical interrupts are handled.
SVC Mode: The Supervisor mode is the software interrupt mode of the processor to start up or reset.
Undefined Mode: The Undefined mode traps when illegal instructions are executed. The ARM core consists
of 32-bit data bus and faster data flow.
THUMB Mode: In THUMB mode 32-bit data is divided into 16-bits and increases the processing speed.
THUMB-2 Mode: In THUMB-2 mode the instructions can be either 16-bit or 32-bit and it increases the
performance of the ARM cortex –M3 microcontroller. The ARM cortex-m3 microcontroller uses only
THUMB-2 instructions.

16. ARM-Cortex Microcontroller
In the present days, the microcontroller vendors are offering 32-bit
microcontrollers based on ARM cortex-m3 architecture. Many embedded system
developers are starting to use these 32-bit microcontrollers for their projects. The
ARM microcontrollers supports for both low-level and high level programming
languages. Some of the traditional microcontroller architectures are made with
many limitations therefore, difficult to use the high level programming language.

17. FEATURES OF ARM MICROPROCESSOR .
● In this designed processor there are only 25 basic instruction types.
● Through registers most of operations are implemented.
● Here every instruction has its own conditions with registers.
● This processor offers multiple modes of addressing.
● Manual stack manipulation is done here.
● Stack addressing and subroutines consist of explicitly programmed techniques.
● Because of 32 bits micro-processor , it is possible to have access to memory and data
manipulation saved in these 32 bits.
● The address range of this processor is widely 26 bit.
● For direct access it allows 64 megabytes of memory.
● It consists of single cycle execution method.

18. ARM APPLICATION .
Here mentioning some of the applications of ARM
1. Portable Media Players, Camcorders: Apple iPod Nano, original Zune 30 GB, Juice Box,
Empeg Car, M6 Mini Player etc.
2. Mobile Phone, PDAs, Cameras: Nokia N93, Samsung Moment, Sony CLIÉ NX60, Canon
PowerShot A470 etc.
3. GPS Navigation Systems: Tom Tom 300, Zarlink GPS receiver, Sun SPOT, Garmin
Navigation Devices etc.
4. Portable Games Consoles: GameBoy Advance, 3DO Interactive Multiplayer, Nintendo 3DS
etc.
5. Set Top Boxes, TVs, Hard Discs, Routers: Asus Tinker Board, Zipit Wireless Messenger,
Acorn Risc PC, Gumstix basix & connex etc.

19. ADVANTAGES .
● They are cheaper as compared to other processors.
● It consumes less power.
● Better battery life than other processors.
● It works faster because it performs one operation at a time.
● Users choose ARM processors because of availability and applications
support.

20. DISADVANTAGES .
● You can not run windows on it very soon because it is not binary
compatible with x86.
● The speeds and memory bandwidths are limited in such cases because
of ARM processor’s clock frequencies.
● Debugging is difficult because of scheduling of instructions.
● The performance of these processors totally depend on execution so if
programmer does not execute it properly then it can take a long time to
work properly.

21. THANK YOU ;) .