Can be used with little or no modifications on different
types of machines

Assembly language programs are portable

Program maintenance is easier

Assembly code tends to be compact

Assembly language programs tend to run faster

Only a well-written assembly language program runs faster
– Easy to write an assembly program that runs slower than
its high-level language equivalent

we program in assembly language because of
Space-efficiency and Time-efficiency

.... specifies an operation and the
locations of its data operands

A ...-bit word typically holds one encoded
instruction

A sequence of instructions, executed one after
another, constitutes a program

Both a program and its data are stored in the main
memory

Looks at the design aspect from a high level

Processor: consists of

Uses digital logic gates and other hardware circuits

Control unit
Datapath
ALU Registers • Implementers are concerned with design of these components

the brains behind the whole
system!

An instruction execution cycle:
 Fetch
 Decode  Store  Execute