This document discusses the architecture of processors. It describes how a CPU is composed of a control unit and arithmetic unit. The control unit retrieves and decodes instructions from main storage and sends signals to other units for execution. Instructions are represented in binary machine language and contain an operation code and addresses. Instruction formats include zero-address, single-address, two-address, and three-address formats depending on how many operands are specified. The instruction decoding process involves storing the instruction in a register, decoding the operation code, and retrieving or storing data at specified addresses.

1. Процессорын архитектур
Лекц 5

2. Процессорын архитектур
• Control unit + Arithmetic unit= CPU
– Control unit
• Retrieval of the instructions stored in the main storage
unit
• Decoding of the retrieved instructions using the
instruction decoder
• According to the decoding, transmission of the
specifications required for the execution of the
instructions to each unit
• Jonh von Neumann
– Sequential control system

3. Sequential control system
(дараалсан удирдлагын систем)

4. Арифметик нэгж
• The official name of the arithmetic unit is
arithmetic and logic unit (ALU).

5. Процессорын ажиллах зарчим
• The data and programs retrieved from the
main storage unit are transferred to the
processor through the data bus. Then the data
subject to processing is temporarily stored in
the "general-purpose register,“ while a part of
the program indicating the procedure of the
process is transferred to the "instruction
register.“

6. Инструкц
• The program is a set of instructions that indicates "do …" to the computer. Since
inside the computer, data is represented in the binary system, instructions are also
represented in the binary system. The instructions represented in the binary
system are called machine language instructions. Regardless of the program
language in which a program is written, at the end it is converted into language
that can be understood by the computer, machine language, in order to be
decoded and executed. Machine language instructions and instruction formats
differ depending on the computer, but, in general terms, they are composed of the
following parts.
– Instruction part: Indicates instructions and operations
– Address part: Specifies the address and register of the main storage unit
subject to processing

7. Инструкц формат
• Zero-address format
The zero-address format performs operations using a
dedicated register called a stack pointer. Currently, zero-address
format computers are not used. The stack pointer is
the register that stores the address to be returned to (return
address) after execution completion.
• Single-address format
The single-address format performs operations between the
content of the main storage unit specified
in the address and the accumulator data. The accumulator
stores operation values and operation results. There are cases
where general-purpose registers are also used as
accumulators.

8. Инструкц формат
• Two-address format
The two-address format specifies two addresses
and uses the address data specified on the main
storage unit.
• Three-address format
The three-address format specifies two addresses
to be used for the operation, and the address
where the operation result is to be stored.

9. Инструкц ачаалах
• The instruction received from the main storage unit is stored in the instruction
register (IR). The length of one word of the main storage unit is 16 bits. It is
supposed that one instruction has 32 bits in the computers used. One
instruction is stored in two words. Therefore, the content of the address of
the main storage unit accessed is sent to the processor twice.
In practice, it is determined beforehand that in one instruction the instruction
part is stored in an even address while the address part is stored in an odd
address.

10. Инструкцийн кодыг тайлах
• The content of the instruction part of the instruction register is transferred
to a device called the decoder. The decoder decodes the type of work
indicated by the instruction and sends the signals for the execution of the
operation to each unit.

11. • On the other hand, the content of the address part of the
instruction register is transferred to the address bus. The content of
the address of the main storage unit specified by the address bus
corresponds to the data subject to processing. According to the
instruction of the instruction part, a read/write signal is sent from
the control unit to the data, subject to processing on the main
storage unit.

12. Санах ойгоос ачаалсан өгөгдлийг хадгалах
• If, as a result of decoding the instruction part and the address part
using the instruction decoder, the instruction is found to say
"Retrieve and transfer to the processor the contents of address 100
of the main storage unit," a place to store the retrieved contents
will be needed. Therefore, a general-purpose register is set in the
arithmetic unit of the processor in order to store the retrieved data.

13. Регистрүүд
• Program counter-програмын тоолуур
• Accumulator-аккумлятор
• Index register-индекс
• Base address register-суурь хаяг
• Program Status Word (PSW)-програмын
төлөв
• Flag register-флаг
• Complement register-гүйцээлт