Lecture 3 Flashcards
(25 cards)
What is the instruction format
The instruction format is the size and arrangment of components
What are the two major components
The function code also called opcode. This specifies the function or the operation performed.
The operand address which specify the locations of the operand
What is the basic instruction format of Memory-Reference , Register and Input and outupt instructions
MR = OPcode = 000 ~ 110
RR = 111, I = 0
IO = 111, I = 1
What is the operation code field of an instruction
This is a groput of bits that define various processor operations such as add, subtract, complement and shift.
What is the address format
This is the part of the instruction format that deals with specifying the address of operands.
What are the main methods
3-address machines;
2-address machines;
1-address machines;
0-address machines.
What is the instruction cycle
The instruction cycle (also known as the fetch–decode–execute cycle, or simply the fetch-execute cycle) is the cycle that the central processing unit (CPU) follows from boot-up until the computer has shut down in order to process instructions.
What is the instruction cycle
Instruction Cycle
Decode Instruction
Read EA from memeory
Execute Instruction
What are the registers involved in each instruction cycle
Memory address registers (MAR): It is connected to System Bus address lines. It specifies the address of a read or write operation in memory.
Memory Buffer Register (MBR): Also called Memory Data Register (MDR). It is connected to the system bus Data Lines. It holds the memory value to be stored, or the last value read from the memory.
Program Counter (PC): Holds the address of the next instruction to be fetched.
Instruction Register (IR): Holds the last instruction fetched
A computer consists of 5 functionally independent main parts
Input
Output
Memory
Arithmetic and Logic Unit
Control Unit
What are the three parts in a CPU
an Arithmetic and Logic Unit (ALU), a Control Unit (CU), and a set of registers
What are logic operations
Logic Operations: Logic operations include NOT, AND, OR, NAND, NOR, XOR.
These operations treat the input data as bit patterns and the result of the operation is also a bit pattern.
What are shift operation
Shift operations include logical shift and arithmetic shift operations
What type of opeartions do the ALU perform
Logic
Shift
Arithmetic operations
What are registers
Registers are fast stand-alone storage locations that hold data temporarily
Mention some types of registers
Data Registers:
Instruction Registers:
Program Counter
What is the control unit for
The control unit controls the operation of each subsystem.
What is the internal memory
A small, but extremely quick memory. It is used for any internal computations that need to be done fast without the added overhead of writing to external memory.
What is the data buffer for
This buffer is a bi-directional device that holds outgoing data until the memory bus is ready for it or incoming data until the CPU is ready for it.
What is the address latch
This group of latches maintain the address that the processor wihses to exhcange data with on the memory bus.
What is the I/O ports
These ports represent the device interfaces that have been incorporated into the processor’s hardware.
What are configuration registers
These registers contain the flags that represent the current configuration of the processor.
What are functions of the processors
i To control the use of main storage to store data and instructions
ii. To control the sequence of operations
iii. To give commands to all parts of the computer system
iv. To carry out processing
Describe the two division of the memory stystem
Primary memory: - Is the one exclusively associated with the processor and operates at the electronics speeds programs must be stored in this memory while they are being executed.
Secondary memory: - Is used where large amounts of data & programs have to be stored, particularly information that is accessed infrequently. Examples: - Magnetic disks & tapes, optical disks (i.e. CD-ROM’s), floppies etc.
