Introduction to computer systems architecture and programming

1. Data Manipulation
Lecture 3

2. Manipulation
• Moving data from one location to another as well as performing operations
such as arithmetic calculations
• The circuitry in a computer that controls the manipulation of data is called
the central processing unit, or CPU
• Mobile internet devices MID
• microprocessors

3. Central Processing Unit (CPU)
1. Arithmetic / Logical Unit (ALU)
2. Control Units (CU)
• Transfer data from memory to registers
• Informs ALU about these register addresses
• Informs ALU which circuitry to activate and in which registers result should be stored
3. Registers
1. General Purpose
2. Special Purpose

4. Central Processing Unit (CPU)

5. CPU Addition

6. Machine Language
• CPUs are designed to recognize instructions encoded as bit patterns. This
collection of instructions along with the encoding system is called the
machine language
• An instruction expressed in this language is called a machine-level
instruction

7. CPU architecture
• Reduced instruction set computer (RISC)
• Complex instruction set computer (CISC)
• PowerPC processors were RISC
• Intel are CISC

8. Instruction categories
1. Date Transfer
• Load, Store, Move I/O instructions (READ, WRITE)
2. Arithmetic/Logic
• AND, OR, XOR, SHIFT, ROTATE
3. Control
• STOP, BRANCH/JUMP ( conditional, unconditional)

9. Dividing values stored in memory
• Step 1. LOAD a register with a value from memory.
• Step 2. LOAD another register with another value from memory.
• Step 3. If this second value is zero, JUMP to Step 6.
• Step 4. Divide the contents of the first register by the second register and
leave the result in a third register.
• Step 5. STORE the contents of the third register in memory.
• Step 6. STOP.

10. Assembly Language
• Readable form of machine language is assembly
• MOV R1, R2
• Assembler

13. Instruction Cycle

14. Communication with peripherals – the
controller
• A controller translates messages
and data back and forth between
forms compatible with the internal
characteristics of the computer and
those of the peripheral device to
which it is attached.
• Port, Buffer
• Interrupt

15. • Parallel Vs serial communication
• Steps taken for standardization USB, FireWire
• If the CPU tries to read data from such a memory location, as in a LOAD
instruction, it will receive a bit pattern from the controller rather than from
memory. Such a communication system is called memory-mapped I/O
• Controllers that can access main memory directly without the need for any
intervention by the CPU referred as Direct Memory Access

16. Program Execution example