2. Topic
Introduction to Computer
Architecture and Organization

3. Computer architecture
The architecture of a computer is the interface between the
machine and the software.
Deals with the functional behavior of a computer system as
viewed by programmer (like the size of a data type – 32 bits
to an integer).
Logical aspects of system implementation as seen by the
programmer.
E.g., instruction sets, instruction formats, data types,
addressing modes.

4. Computer organization
Deals with structural relationships that are not
visible to the programmer(like clock frequency or the
size of the physical memory).
All physical aspects of computer systems,
E.g. circuit design, control signals, memory types

5. Why study computer organization
and architecture?
Design better programs, including system software
such as compilers, operating systems, and device
drivers.
Optimize program behavior.
Evaluate computer system performance.
Understand time, space, and price tradeoffs

6. What is Computer Architecture
Computer Architecture = ISA+CO
Instruction Set Architecture (ISA)
the computer does (logical view)
Computer Organization (CO)
the ISA is implemented (physical view)

7. Instruction Set Architecture
Critical interface between hardware and software
Standardizes instructions, machine language bit
patterns, etc.
Advantage: different implementations of the same
architecture
Disadvantage: sometimes prevents using new
innovations

8. continue
Examples (versions)
Introduced in
Intel
(8086, 80386, Pentium, ...) 1978
IBM Power (Power 2, 3, 4, 5)
1985
HP PA-RISC (v1.1, v2.0)
1986
MIPS
(MIPS I, II, III, IV, V)
1986
Sun Sparc (v8, v9)
1987
Digital Alpha(v1, v3)
1992
PowerPC (601, 604, …)
1993

9. CPUs: the heart of computing
systems

10. Inside microprocessor

11. Other architecture styles
Accumulator architecture
Stack
Register (load store)
Register-Memory
Memory-Memory

12. Other architecture styles

13. Other architecture styles
Accumulator architecture
one operand (in register or memory), accumulator almost always
implicitly
used
Stack
zero operand: all operands implicit (on TOS)
Register (load store)
three operands, all in registers
Loads and stores are the only instructions accessing memory (i.e. with a
memory (indirect) addressing mode
Register-Memory
two operands, one in memory
Memory-Memory
three operands, may be all in memory

14. END