Ch 11: Real-Time Interrupts & Timer Programming

Technical study of timer channels, programming PIT control word registers (port 0x43), divisor calculations (1193180 / frequency), hooking timer tick interrupt 08h, and rendering on-screen digital clocks.

171 Questions171 MCQs0 Short Questions0 Long Questions

🎯 Exam Practice Papers

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Timed practice exam simulation for CS401 - Computer Architecture and Assembly Language Programming.

Showing 41 – 50 of 171 Questions

Page 5 of 18

Q41

📝 Short Q📘 CS401📑 Lec 11🏷️ 11.1. Multitasking and Multithreading (Context Switch State Saving)Easy🔁⭐💡📄🎓VU🏛️VU

In x86 assembly language multitasking concepts, fill in the blanks regarding thread context switching: During a thread context switch, the processor state consisting of __________ and __________ must be saved onto the thread's stack before switching execution.

💻 assembly Snippet

; Thread Context Switch:
pusha    ; Push all general-purpose registers
pushf    ; Push FLAGS register
mov [tcb_sp], sp ; Save current SP in TCB

Q42

❓ MCQ📘 CS401📑 Lec 11🏷️ 11.1. High-Level Language Interface (NASM extern and global Modular Directives)Easy🔁⭐💡📄🎓VU🏛️VU

In NASM syntax, an imported symbol defined in an external object file is declared using the __________ directive, while an exported symbol visible to other modules is declared using the __________ directive.

💻 assembly Snippet

extern _printf ; External directive for imported symbol
global _main   ; Global directive for exported symbol

A.Global directive, External directive
B.External directive, Global directive
C.Home Directive, Foreign Directive
D.Import directive, Export directive

Q43

🧠 Long Problem📘 CS401📑 Lec 11🏷️ 11.1. High-Level Language Interface (C and Assembly Pointer Interfacing)Hard⭐💡📄🎓VU🏛️VU

Given the following 32-bit x86 assembly function `swap` that exchanges two integer values via pointers: ```assembly [section .text] global swap swap: mov ecx, [esp+4] ; copy parameter p1 to ecx mov edx, [esp+8] ; copy parameter p2 to edx mov eax, [ecx] ; copy *p1 into eax xchg eax, [edx] ; exchange eax with *p2 mov [ecx], eax ; copy eax into *p1 ret ; return from function ``` Write a complete C language main program that declares, links, and calls this assembly routine to swap two integer variables.

💻 assembly Snippet

; Assembly Routine (swap.asm):
[section .text]
global _swap
_swap:
    mov ecx, [esp+4] ; p1 pointer
    mov edx, [esp+8] ; p2 pointer
    mov eax, [ecx]   ; eax = *p1
    xchg eax, [edx]  ; *p2 = *p1, eax = old *p2
    mov [ecx], eax   ; *p1 = old *p2
    ret

Q44

❓ MCQ📘 CS401📑 Lec 11🏷️ 11.1. High-Level Language Interface (NASM extern and global Directives)Easy🔁⭐💡📄🎓VU🏛️VU

In NASM syntax, an imported symbol defined in an external object file is declared with the __________, while an exported symbol visible to other modules is declared with the __________.

💻 assembly Snippet

extern _printf ; External directive for imported symbol
global _main   ; Global directive for exported symbol

A.Global directive, External directive
B.External directive, Global directive
C.Home Directive, Foreign Directive
D.Foreign Directive, Home Directive

Q45

📝 Short Q📘 CS401📑 Lec 11🏷️ 11.1. High-Level Language Interface (32-Bit x86 Caller-Saved Scratch Registers EAX, ECX, EDX)Easy⭐💡📄🎓VU🏛️VU

In standard 32-bit x86 C calling conventions (cdecl / stdcall), which general-purpose registers are designated as caller-saved (scratch) registers whose values may be modified without preservation across function calls?

💻 assembly Snippet

; EAX, ECX, EDX are volatile scratch registers in cdecl
; EBX, ESI, EDI, EBP, ESP are callee-saved non-volatile registers

Q46

📝 Short Q📘 CS401📑 Lec 11🏷️ Multitasking and Thread Local VariablesMedium⭐💡🌟📄🎓VU🏛️VU

Which register is utilized for accessing thread-local variables in assembly language function stack frames?

💻 assembly Snippet

push bp
mov bp, sp
sub sp, 2

Q47

📝 Short Q📘 CS401📑 Lec 11🏷️ Multitasking Kernel as TSRMedium⭐💡🌟📄🎓VU🏛️VU

Explain the purpose of each instruction in the following code snippet taken from a Multitasking TSR caller program: `mov al, [chars+bx]` `mov [es:40], al` `inc bx`

💻 assembly Snippet

mov al, [chars+bx]
mov [es:40], al
inc bx

Q48

📝 Short Q📘 CS401📑 Lec 11🏷️ Multitasking Kernel and Context SwitchingMedium⭐💡📄🎓VU🏛️VU

Define multitasking in computer systems and explain how context switching enables concurrent execution.

💻 assembly Snippet

timer:
    push ax
    push bx
    ; Save context into PCB, switch tasks, restore next context
    iret

Q49

❓ MCQ📘 CS401📑 Lec 11🏷️ Multitasking Kernel and Thread ExecutionEasy⭐💡📄🎓VU🏛️VU

In a multithreaded architecture, each thread maintains its own private stack frame, enabling threads to have independent ________ function calls, parameters, and variables.

💻 assembly Snippet

push bp
mov bp, sp
sub sp, 4

A.Global
B.Local
C.Legal
D.Illegal

Q50

📝 Short Q📘 CS401📑 Lec 11🏷️ Multitasking Kernel as TSRMedium🔁⭐💡📄🎓VU🏛️VU

Provide inline comments explaining the exact operation of each instruction in the following snippet taken from a Multitasking TSR caller program: `mov al, [chars+bx]` `mov [es:40], al` `inc bx`

💻 assembly Snippet

mov al, [chars+bx]
mov [es:40], al
inc bx

Ch 11: Real-Time Interrupts & Timer Programming

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Mid Term Examination

Final Term Examination

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Mid Term Examination

Final Term Examination

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