assembly language chapter

1. HAMAR UNIVERSITY
LECTURER : ENG MUSTAF KHALID AHMED ( MK )
COURSE : ASSEMBLY LANGUAGE

2. WHAT IS ASSEMBLY LANGUAGE
⚫ An assembly language is a low-level programming
language for microprocessors and other programmable
devices.
⚫ It is the most basic programming language available
for any processor.
⚫ A processor understands only machine language
instructions, which are strings of 1's and 0's.
⚫However, machine language is too obscure and
complex for using in software development , instead
low level assembly language is used .

3. Flow of compilation

4. COMPILATION FLOW EXPLAINED
⚫ Preprocessing : is the first pass of any C compilation.
It processes include-files, conditional compilation
instructions and macros.
⚫ Compilation : is the second pass. It takes the output of
the preprocessor, and the source code, and generates
assembler source code.
⚫ Assembly : is the third stage of compilation. It takes
the assembly source code and produces an
assembly listing with offsets. The assembler
output is stored in an object file.

5. ⚫Linking : is the final stage of compilation. It takes
one or more object files or libraries as input and
combines them to produce a single (usually
executable) file. In doing so, it resolves references
to external symbols, assigns final addresses to
procedures/functions and variables, and revises code
and data to reflect new addresses (a process called
relocation).

6. BASIC FEATURE OF PC HARDWARE
⚫Motherboard : The motherboard serves to
connect all of the parts of a computer
together. The cpu, memory, hard drives,
optical drives, video card, sound card and
other ports and expansion cards all
connect to the motherboard directly or via
cables.

7. MOTHERBOARD EXPLAINED

8. ⚫BIOS :lowest-level software in the computer, acts
as an interface between the hardware and the
operating system .
⚫ ROM : is nonvolatile. ROM chips contain
permanently written data, called firmware (your
BIOS lives here).
⚫ RAM : RAM devices are used in computer
systems as the main memory. RAM is considered
volatile memory, which means that the stored
information is lost when there is no power.

9. PROCESSING DEVICES

10. ⚫Control unit : Acontrol unit (CU) handles all
processor control signals . It directs all input and
output flow, fetches code for instructions from
microprograms and directs other units and models
by providing control and timing signals.
⚫ALU : AnALU performs basic arithmetic and logic
operations. Examples of arithmetic operations are
addition, subtraction, multiplication, and division.
Examples of logic operations are comparisons of values
such as NOT,AND, and OR.
⚫Registers : In a computer, a register is one of a
small set of data holding places that are part of a
computer processor .Aregister may hold a
computer instruction , a storage address, or any kind
of data.

11. ⚫Bus : The CPU moves data around the computer
on pathways that interconnect it to all the other
components on the motherboard. These pathways
are called 'buses‘
⚫Types of Bus
⚫Address - the components pass memory addresses
to one another over the address bus.
⚫Control - used to send out signals to coordinate and
manage the activities of the motherboard
components.
⚫Data - transferred between peripherals, memory and
the CPU. Obviously, the data bus can be a very busy
pathway.

12. NUMBER SYSTEM
⚫ A set of values used to represent different quantities is known as
Number System
 Types of number system
Binary - Or base 2. There are only two numbers in binary, 0 and
Because computers use a sequence of switches that can be on or off (also called
a bit), base 2 works very well for them. Math in base 2 is pathetically simple,
but incredibly time consuming
Octal - Or base 8. Uses the numbers 0 to 7. There are eight bits in a byte which
is used very often in the computer field. (A bit is great, but it's too small to hold
any useful data, thus the byte is used.) Math in octal is more complicated than
decimal
Decimal - Or base 10. Uses the numbers 0-9. I'm sure you're familiar with
this system. Computers only display numbers in decimal, they actually do all
their work in binary. Math is quite simple with this number system, although
some may argue.
Hexadecimal - Or base 16. Uses the numbers 0-F. Yes, I said F. Because there
are 16 values per place holder, five new numbers had to be created. Those
numbers are A, B, C, D, E, and F (Original isn't it?). "A" has a value of 10, "B"
is 11, and so on

13. NUMBER SYSTEM
SYSTEM BASE DIGITS
BINARY 2 01
OCTAL 8 01234567
DECIMAL 10 0123456789
HEXADECIMAL 16 0123456789ABCDE
F

14. •Thank you
•Any question