Microprocessor Flashcards
What is the primary function of the AX register?
The AX register is primarily used for arithmetic and logical operations
What is the structure of the AX register?
The AX register is divided into two 8-bit registers: AH (high) and AL (low)
Why is the structure of the AX register significant?
It allows for more flexible data manipulation at the byte level
What happens when the instruction ADD AX, BX is executed?
The contents of BX are added to AX and the result is stored in AX
Fill in the blank: The AX register is often the default register for many operations, especially those involving _______.
multiplication and division
What is the function of the BX register?
The BX register is used as a base pointer for memory addressing.
In which addressing modes is the BX register particularly useful?
Indexed addressing modes.
What does the BX register hold?
The base address of a data structure.
How is the BX register structured?
Divided into two 8-bit registers: BH (high) and BL (low).
What happens in the instruction MOV AX, [BX]?
The contents of the memory location pointed to by BX are moved into AX.
What is the primary function of the CX register?
Used as a loop counter in iterative operations
The CX register controls the number of iterations in loops.
How is the CX register structured?
Divided into two 8-bit registers: CH (high) and CL (low)
This allows the CX register to hold 16 bits of data.
What happens when the instruction LOOP label is executed?
Decrements CX by one and jumps to the label if CX is not zero
This creates a loop that continues until CX reaches zero.
Fill in the blank: The CX register is often used in conjunction with _______ to control iterations.
[loop instructions]
What is the function of the DX register?
Used for I/O port addressing and holding the high-order word of a product in multiplication or division operations.
The DX register plays a crucial role in arithmetic operations and interfacing with hardware.
What are the components of the DX register?
Divided into two 8-bit registers: DH (high) and DL (low).
This division allows for more granular access to the data stored in the DX register.
In a multiplication operation involving large numbers, where is the high-order word of the product stored?
In the DX register.
The low-order word of the product is stored in AX during such operations.
What does the instruction MUL BX do?
Multiplies AX by BX and stores the result in DX:AX.
The result is a combination of both the high and low-order words, allowing for accurate representation of large products.
Fill in the blank: The DX register is used for _______ port addressing.
I/O
This function is essential for communication between the CPU and peripheral devices.
