Ch 04: Bit Manipulation and Shifts

Covers bitwise logic manipulations, clearing/setting/toggling specific bits, arithmetic vs logical shifts, fast multiplication and division algorithms by powers of 2, and extended-precision math.

198 Questions198 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 181 – 190 of 198 Questions

Page 19 of 20

Q181

❓ MCQ📘 CS401📑 Lec 4🏷️ 4.1. Shift InstructionsEasy🔁⭐💡📄🎓VU🏛️VU

The diagram `| 0 | ---> [ 1 1 0 1 0 0 0 ] ---> | C |` (where 0 enters the MSB and the LSB exits into the Carry Flag) illustrates which assembly instruction?

💻 assembly Snippet

shr ax, 1

A.SHL
B.SAR
C.SHR
D.SAL

Q182

❓ MCQ📘 CS401📑 Lec 4🏷️ 4.1. Shift InstructionsEasy🔁⭐💡📄🎓VU🏛️VU

The diagram `| C | <--- [ 1 1 0 1 0 0 0 ] <--- | 0 |` (where 0 enters the LSB and the MSB exits into the Carry Flag) illustrates which assembly instruction?

💻 assembly Snippet

shl ax, 1

A.SHL
B.SAR
C.SHR
D.SAL

Q183

❓ MCQ📘 CS401📑 Lec 4🏷️ 4.1. Shift InstructionsEasy🔁⭐💡📄🎓VU🏛️VU

True or False: The shift instructions SHR (Shift Logical Right) and SAL (Shift Arithmetic Left) perform identical bit operations.

💻 assembly Snippet

shr ax, 1  ; Shift Right
sal ax, 1  ; Shift Left

A.TRUE
B.FALSE

Q184

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.1. Stack OperationsMedium⭐💡📄🎓VU🏛️VU

Explain the functions of the Stack Pointer (SP) and Base Pointer (BP) registers in the 8086 microprocessor, and specify their default segment associations.

💻 assembly Snippet

; Stack Frame Access using BP and SP
push bp
mov bp, sp       ; Set up stack frame reference
mov ax, [bp + 4] ; Access parameter passed on stack relative to SS

Q185

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingMedium⭐💡📄🎓VU🏛️VU

Explain how basic binary multiplication can be performed using shifting and addition operations (the Shift-and-Add algorithm).

💻 assembly Snippet

; Shift-and-Add Binary Multiplication Concept
mov ax, 0      ; Accumulator for result
mov bx, 5      ; Multiplicand
mov cx, 3      ; Multiplier

Q186

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingEasy⭐💡📄🎓VU🏛️VU

Compare Shift Logical Right (SHR) and Shift Logical Left (SHL) / Shift Arithmetic Left (SAL) instructions in 8086 assembly language in terms of bit insertion, shift direction, and Carry Flag updates.

💻 assembly Snippet

; SHR and SHL/SAL Examples
mov ax, 0x0008  ; AX = 8 (0000 0000 0000 1000b)
shr ax, 1       ; AX = 4, CF = 0 (Logical Right Shift)
shl ax, 1       ; AX = 8, CF = 0 (Logical Left Shift)

Q187

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingHard⭐💡📄🎓VU🏛️VU

What is the primary difference between Shift Logical Right (SHR) and Shift Arithmetic Right (SAR) in 8086 assembly language, and why is SAR required for signed integers?

💻 assembly Snippet

; Signed vs Unsigned Right Shift Comparison
mov al, -8      ; AL = 0xF8 (1111 1000b in 2's complement)
shr al, 1       ; AL = 0x7C (0111 1100b = +124 decimal) -> Incorrect signed division!
mov al, -8      ; AL = 0xF8
sar al, 1       ; AL = 0xFC (1111 1100b = -4 decimal)   -> Correct signed division!

Q188

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingEasy⭐💡📄🎓VU🏛️VU

Explain the operations of Rotate Right (ROR) and Rotate Left (ROL) instructions in 8086 assembly language, detailing bit movements, operand bit-widths, and Carry Flag (CF) updates.

💻 assembly Snippet

; ROR and ROL Instruction Usage
mov al, 0x81    ; AL = 1000 0001b
ror al, 1       ; AL = 1100 0000b (0xC0), CF = 1
rol al, 1       ; AL = 1000 0001b (0x81), CF = 1

Q189

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingMedium⭐💡📄🎓VU🏛️VU

How do Rotate Through Carry Right (RCR) and Rotate Through Carry Left (RCL) instructions operate in 8086 assembly language, and why are they described as 9-bit or 17-bit rotations?

💻 assembly Snippet

; RCR and RCL Usage Example
clc             ; Clear Carry Flag (CF = 0)
mov al, 0x81    ; AL = 1000 0001b
rcr al, 1       ; CF inserted at MSB: AL = 0100 0000b (0x40), CF = 1
rcl al, 1       ; CF (1) inserted at LSB: AL = 1000 0001b (0x81), CF = 0

Q190

📝 Short Q📘 CS401📑 Lec 4🏷️ 4.2. Bit Manipulation & ShiftingMedium⭐💡📄🎓VU🏛️VU

Outline the systematic steps of the Shift-and-Add Multiplication Algorithm implemented in 8086 assembly language.

💻 assembly Snippet

; 8086 Shift-and-Add Multiplication Algorithm
mov ax, 0          ; Initialize result accumulator
mov bx, 13         ; Multiplicand
mov cx, 5          ; Multiplier

mult_loop:
shr cx, 1          ; Shift LSB of multiplier into CF
jnc skip_addition
add ax, bx         ; Add multiplicand if bit was 1

skip_addition:
shl bx, 1          ; Always shift multiplicand left
cmp cx, 0
jnz mult_loop      ; Repeat until multiplier is 0

Ch 04: Bit Manipulation and Shifts

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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