Ch 05: Subroutines and Stack Architecture

Examines stack memory allocation, downward growth of the stack, return address pushing, caller vs callee register preservation, and avoiding stack misalignment bugs.

222 Questions222 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 21 – 30 of 222 Questions

Page 3 of 23

Q21

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. String Instructions (STOSB and Direction Flag)Easy🔁⭐💡📄🎓VU🏛️VU

In string instructions like STOSB, when the Direction Flag (DF) is clear (DF = 0), how is the Destination Index (DI) register modified?

💻 assembly Snippet

CLD
STOSB

A.Incremented by 1
B.Incremented by 2
C.Decremented by 1
D.Decremented by 2

Q22

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. String Operations and Repeat Prefixes (REP STOSW)Easy🔁⭐💡📄🎓VU🏛️VU

When executing string instructions with the repeat prefix (e.g., `REP STOSW`), how is the Count Register (CX) modified after each iteration?

💻 assembly Snippet

REP STOSW

A.Decremented by 1
B.Decremented by 2
C.Incremented by 1
D.Incremented by 2

Q23

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. String Instructions (STOSB Index Register Pointer Update)Easy🔁⭐💡📄🎓VU🏛️VU

In the STOSB (Store String Byte) instruction, by how many bytes is the index register modified (incremented or decremented depending on the Direction Flag)?

💻 assembly Snippet

STOSB

Q24

📝 Short Q📘 CS401📑 Lec 5🏷️ 5.1. Program FlowEasy⭐💡📄🎓VU🏛️VU

What assembly language instructions are used to perform permanent (unconditional) and temporary (subroutine) program execution diversions?

💻 assembly Snippet

jmp permanent_label ; Permanent diversion
call subroutine_label ; Temporary diversion

Q25

🧠 Long Problem📘 CS401📑 Lec 5🏷️ 5.6. Local VariablesHard⭐💡🌟📄🎓VU🏛️VU

Describe the concept, stack implementation, lifecycle, and scope of local variables in assembly language subroutines.

💻 assembly Snippet

push bp
mov bp, sp
sub sp, 4 ; Allocates 4 bytes for local variables

Q26

🧠 Long Problem📘 CS401📑 Lec 5🏷️ 5.6. Local Variables and Stack Frame ManagementHard⭐💡🌟📄🎓VU🏛️VU

Explain how local variables (such as 'swapflag' in bubble sort) are created, accessed, and managed on the stack frame during subroutine execution in x86 assembly language.

💻 assembly Snippet

push bp
mov bp, sp
sub sp, 2 ; Allocates 2 bytes (1 word) for local variable 'swapflag'

Q27

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. Subroutines and Stack (PUSH Register Non-Destructive Mechanics)Easy🔁⭐💡📄🎓VU🏛️VU

What happens to the register `AX` upon executing the assembly instruction `PUSH AX`?

💻 assembly Snippet

push ax ; Decrements SP by 2 and copies contents of AX to [SS:SP]

A.AX register will reside on the stack
B.A copy of AX will go on the stack
C.The value of AX disappears after moving on stack
D.Stack will send an acceptance message

Q28

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. Subroutines and Stack (SS:SP Addressing)Easy🔁⭐💡📄🎓VU🏛️VU

The 20-bit physical memory address of the stack top is computed using which segment and offset register pair?

A.SS:SP combination
B.SS:SI combination
C.ES:BP combination
D.ES:SP combination

Q29

❓ MCQ📘 CS401📑 Lec 5🏷️ 5.1. Subroutines and Stack (PUSH Execution Mechanics)Easy🔁⭐💡📄🎓VU🏛️VU

When an item is pushed onto a standard downward-growing x86 stack, how does the Stack Pointer (`SP`) operate relative to copying data?

A.First decremented and then element copied on to the stack
B.First incremented and then element copied on to the stack
C.Decremented after the element copied on to the stack
D.Incremented after the element copied on to the stack

Q30

📝 Short Q📘 CS401📑 Lec 5🏷️ 5.1. Subroutines and Stack (CALL and RET Relationship)Medium⭐💡📄🎓VU🏛️VU

Discuss the relationship between the subroutine instructions `CALL` and `RET` regarding whether they operate as hardware-dependent or independent operations.

💻 assembly Snippet

call my_subroutine ; Pushes IP and jumps
;
my_subroutine:
    ret ; Pops return address into IP

Ch 05: Subroutines and Stack Architecture

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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