Computer Architecture & Assembly Language MCQs with Answers
Practice important Computer Architecture & Assembly Language MCQs with answers and explanations.
Chapter: 14
Q321:
What is the purpose of the AH register in the INT 14 - SERIAL - READ CHARACTER FROM PORT service?
A. Set baud rate
B. Read character
C. Line status
D. Modem status
Correct Answer:
C
Chapter: 14
Q322:
Which port range is used to access COM1 for serial communication?
A. 3F8-3FF
B. 2F8-2FF
C. 3F0-3F7
D. 2E8-2EF
Correct Answer:
A
Chapter: 14
Q323:
What is indicated by a '101' value in the interrupt identification register?
A. Timer interrupt
B. Modem status interrupt
C. Timeout interrupt
D. Data received
Correct Answer:
A
Chapter: 14
Q324:
Which register must be set to enable interrupt generation by the serial port?
A. 3FC
B. 3FA
C. 3F9
D. 3FB
Correct Answer:
D
Chapter: 14
Q325:
What is the purpose of the line control register in serial port programming?
A. Set modem status
B. Set baud rate
C. Control line status
D. Enable interrupts
Correct Answer:
C
Chapter: 14
Q326:
In the given assembly program, what does the instruction mov ax, 0xb800 do?
A. Clear screen
B. Point to video memory
C. Set baud rate
D. Write character to port
Correct Answer:
B
Chapter: 14
Q327:
Which register holds the interrupt identification in the provided code example?
A. 3F8
B. 3FC
C. 3FA
D. 3F9
Correct Answer:
C
Chapter: 14
Q328:
What is the function of rep stosw in the code example?
A. Receive data
B. Transmit data
C. Clear the screen
D. Set baud rate
Correct Answer:
C
Chapter: 14
Q329:
Which instruction in the code sets the line settings to 9600, 8, N, 1?
A. mov ax, 0xb800
B. mov al, 0xE3
C. mov dx, 0x3FA
D. mov dx, 0x3F8
Correct Answer:
B
Chapter: 14
Q330:
What does the instruction out 0x20, al do in the context of the provided code?
A. Initialize port
B. Set baud rate
C. End of interrupt
D. Write character to port
Correct Answer:
C
Chapter: 14
Q331:
In the code, what does the command mov dx, 0x3FC refer to?
A. Data register
B. Interrupt register
C. Modem control register
D. Line status register
Correct Answer:
C
Chapter: 14
Q332:
What happens when the condition cmp word [cs:screenpos], 4000 is true in the provided code?
A. Screen is cleared
B. Data is transmitted
C. Program terminates
D. Interrupt is generated
Correct Answer:
A
Chapter: 14
Q333:
Which command enables the receiver data interrupt in the provided code example?
A. or al, 1
B. mov dx, 0x3F9
C. mov al, 0xE3
D. in al, 0x21
Correct Answer:
A
Chapter: 15
Q334:
What mode allows a processor to operate in 32-bit mode?
A. Real Mode
B. Protected Mode
C. Compatibility Mode
D. 16-bit Mode
Correct Answer:
B
Chapter: 15
Q335:
How is the processor switched to protected mode?
A. Set CR0 to 0
B. Set CR1 to 1
C. Set the least significant bit of CR0
D. Set the most significant bit of CR1
Correct Answer:
C
Chapter: 15
Q336:
Which of the following is not a 32-bit register?
A. EAX
B. EBX
C. AX
D. EFLAGS
Correct Answer:
C
Chapter: 15
Q337:
What is the memory access capability of a 32-bit address register?
A. 1MB
B. 4GB
C. 8GB
D. 16GB
Correct Answer:
B
Chapter: 15
Q338:
What are the two new segment selectors introduced in 386 processors?
A. FS and GS
B. AX and BX
C. CS and DS
D. EAX and EBX
Correct Answer:
A
Chapter: 15
Q339:
What is the role of the GDT in protected mode?
A. To store instructions
B. To store global descriptors
C. To store local descriptors
D. To store memory data
Correct Answer:
B
Chapter: 15
Q340:
What does the RPL field in a selector indicate?
A. Requested Privilege Level
B. Register Protection Level
C. Requested Priority Level
D. Register Privilege Level
Correct Answer:
A