Ch 07: Video Memory & Screen Display

Covers direct text manipulation on 80x25 character screens, calculating screen offsets ((Row * 80 + Col) * 2), attribute byte structure (foreground, background, blink bit), and converting binary values to ASCII strings.

264 Questions264 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.

Showing 121 – 130 of 264 Questions

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Q121

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (ASCII Digit Conversion via Adding 0x30)Easy🔁⭐💡📄🎓VU🏛️VU

To convert a single numeric decimal digit (0–9) to its corresponding ASCII character representation in assembly language, which arithmetic operation is performed?

💻 assembly Snippet

add al, 0x30 ; Converts numeric value in AL (0-9) to ASCII character ('0'-'9')

A.Add 0x30 to the digit
B.Subtract 0x30 from the digit
C.Add 0x61 to the digit
D.Subtract 0x61 from the digit

Q122

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. String Instructions (SCAS Primitive Subtraction Operation)Easy🔁⭐💡📄🎓VU🏛️VU

Which underlying mathematical operation is executed during the execution of the `SCAS` (Scan String) primitive instruction to update processor flags?

💻 assembly Snippet

scasb ; Performs internal subtraction (AL - [ES:DI]) to set flags

A.Division
B.Multiplication
C.Addition
D.Subtraction

Q123

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (Screen Memory Byte Offset 160 Coordinates)Easy🔁⭐💡📄🎓VU🏛️VU

Executing the instruction `mov word [ES:160], 0x1230` renders character '0' on screen at which coordinate position?

A.First column of second row
B.Second column of first row
C.Second column of second row
D.First column of third row

Q124

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. String Instructions (Direction Flag DF Set for Autodecrementing Pointers)Easy🔁⭐💡📄🎓VU🏛️VU

If string processing moves from higher memory addresses towards lower memory addresses (autodecrementing pointers `SI` / `DI`), what is the state of the Direction Flag (`DF`)?

💻 assembly Snippet

std ; Sets DF = 1 (causes string instructions to autodecrement SI/DI)

A.DF is cleared
B.ZF is cleared
C.ZF is set
D.DF is set

Q125

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (Attribute Byte Bit 6 Background Red)Easy🔁⭐💡📄🎓VU🏛️VU

In standard text-mode video RAM attribute byte formatting (`B IRGB I rgb`), which bit position represents the Red (R) component of the background color?

A.Bit 0
B.Bit 2
C.Bit 4
D.Bit 6

Q126

📝 Short Q📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (Screen Scroll-Up Assembly Routine)Medium🔁⭐💡📄🎓VU🏛️VU

Write and describe the assembly language subroutine used to scroll up the text mode screen display.

💻 assembly Snippet

mov ax, 0xb800
mov es, ax
mov ds, ax
rep movsw
rep stosw

Q127

📝 Short Q📘 CS401📑 Lec 7🏷️ 7.1. String Instructions (LES vs LDS Pointer Loading Instructions)Easy🔁⭐💡📄🎓VU🏛️VU

What is the difference between the `LES` and `LDS` pointer loading instructions in x86 assembly language?

💻 assembly Snippet

les di, [far_ptr] ; Loads offset into DI and segment into ES
lds si, [far_ptr] ; Loads offset into SI and segment into DS

Q128

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (Screen Memory Byte Offset 160 Coordinates)Easy🔁⭐💡📄🎓VU🏛️VU

The execution of the instruction `mov word [ES : 160], 0x1230` will print a character on the screen at:

💻 assembly Snippet

; Offset = (Row * 80 + Column) * 2
; For Row 2 (index 1), Column 1 (index 0): Offset = (1 * 80 + 0) * 2 = 160

A.First column of second row
B.Second column of first row
C.Second column of second row
D.First column of third row

Q129

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. String Instructions (STOSW and CX Iteration Decrement)Easy🔁⭐💡📄🎓VU🏛️VU

After the execution of a word string instruction (such as `STOSW`) with repeat prefix (`REP`), how will register `CX` be updated?

💻 assembly Snippet

rep stosw ; Decrements CX by 1 per word stored

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

Q130

❓ MCQ📘 CS401📑 Lec 7🏷️ 7.1. Video Display Architecture (Standard 7-Bit ASCII Range 128 Characters)Easy🔁⭐💡📄🎓VU🏛️VU

How many characters are defined in standard 7-bit ASCII?

A.512
B.256
C.128
D.64

Ch 07: Video Memory & Screen Display

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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