Ch 08: String Instructions and Primitives

Comprehensive study of x86 string primitives operating across DS:SI and ES:DI, hardware-accelerated memory copy, screen clearing via STOSW, string length calculation via SCASB, and string comparison via CMPSB.

307 Questions307 MCQs0 Short Questions0 Long Questions

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CS401 - Computer Architecture and Assembly Language Programming Examination Practice

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

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📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsMedium🔁⭐💡📄🎓VU🏛️VU

Explain the Divide Overflow Error (Interrupt 0) in x86 Assembly Language.

💻 assembly Snippet

mov ax, 0x8432
mov bl, 2
div bl

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsEasy⭐💡📄🎓VU🏛️VU

For what purpose is the INT 4 interrupt reserved in x86 architecture?

💻 assembly Snippet

add al, 0x7F
into

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsEasy🔁⭐💡📄🎓VU🏛️VU

What is the Trap Flag (TF) in x86 architecture, and what is its primary function?

💻 assembly Snippet

pushf
pop ax
or ax, 0x0100
push ax
poplf

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsMedium🔁⭐💡📄🎓VU🏛️VU

Why are the Interrupt Flag (IF) and Trap Flag (TF) automatically cleared when an Interrupt Service Routine (ISR) is invoked?

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsEasy🔁⭐💡📄🎓VU🏛️VU

What changes occur in the stack when an INT instruction is executed in x86 assembly language?

💻 assembly Snippet

int 0x21

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.2. Hooking an InterruptMedium🔁⭐💡📄🎓VU🏛️VU

Why are CLI and STI instructions used when hooking an interrupt in x86 assembly language?

💻 assembly Snippet

cli
mov [es:0x20*4], offset my_isr
mov [es:0x20*4+2], cs
sti

❓ MCQ📘 CS401📑 Lec 8🏷️ 8.1. InterruptsEasy🔁⭐💡📄🎓VU🏛️VU

Which x86 software interrupt is dedicated to handling arithmetic overflow conditions (triggered by the INTO instruction)?

💻 assembly Snippet

add ax, bx
into

A.INT 1
B.INT 2
C.INT 3
D.INT 4

🧠 Long Problem📘 CS401📑 Lec 8🏷️ 8.2. Hooking an InterruptHard🔁⭐💡📄🎓VU🏛️VU

Write a complete x86 assembly language program to hook and implement a custom 'Break Interrupt Service Routine' (INT 1 / INT 3 Breakpoint Interrupt) that displays a message on screen when triggered.

💻 assembly Snippet

int 3

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When an Interrupt Service Routine (ISR) finishes execution, how does the x86 CPU restore processor context and resume execution of the interrupted program?

💻 assembly Snippet

iret

Q10

📝 Short Q📘 CS401📑 Lec 8🏷️ 8.1. InterruptsEasy🔁⭐💡📄🎓VU🏛️VU

At which physical memory address in the Interrupt Vector Table (IVT) is the 4-byte segment:offset interrupt vector for INT 10h stored?

💻 assembly Snippet

mov ax, [0x0040] ; INT 10h Offset
mov dx, [0x0042] ; INT 10h Segment

Ch 08: String Instructions and Primitives

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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