assembly & computer org

What base is the binary number system?

Base 2

Convert binary 1011 to decimal

11

What is the result of 1 + 1 in binary?

10 (carry 1)

What is the 2's complement of binary 0010?

1110

How is overflow detected in binary addition?

When the carry into the MSB ≠ carry out of the MSB.

What does an AND gate output?

1 only if both inputs are 1.

What gate produces the opposite of its input?

NOT gate

What is the identity for A + 0 in Boolean algebra?

A

Which gate outputs 1 if inputs are different?

XOR gate

DeMorgans Law

A law about logical operations that describes how to negate expressions formed with and and or operations.

What is the key difference between combinational and sequential logic?

Sequential logic has memory (depends on past inputs)

What does a D flip-flop do?

Stores the value of D on the rising clock edge

What is the purpose of a clock in sequential circuits?

Synchronizes state changes

Which flip-flop toggles its state when input is 1?

T flip-flop

What is a register?

A group of flip-flops used to store multiple bits

What are the main components of the Von Neumann architecture?

CPU, memory, I/O, and a single shared bus

What does the Program Counter (PC) do?

Holds the address of the next instruction

What is the Instruction Register (IR)?

Holds the currently executing instruction

Define "fetch-decode-execute" cycle

The basic CPU process: get instruction, understand it, then run it

What is assembly language?

A low-level, human-readable form of machine code

What does the instruction MOV AX, BX do?

Copies the value in BX into AX

What is the role of a label in assembly?

Marks a location in code for jumps or branches

What does ADD instruction do?

Performs integer addition

What instruction performs an unconditional jump?

JMP

What is a conditional branch?

A jump that occurs only if a condition is true (e.g., JE, JNE)

What does CMP do in assembly?

Compares two operands by subtracting them, affecting flags

What is the Zero Flag (ZF) used for?

Indicates result of zero after a comparison or operation

What does the CALL instruction do?

Jumps to a procedure and saves return address on the stack

What does RET do?

Returns to the instruction after a CALL

What is the stack used for in procedures?

Storing return addresses, parameters, and local variables

What do PUSH and POP do?

Add to and remove from the stack (LIFO order)

What is direct addressing?

The operand holds the address of the value

What is immediate addressing?

The operand holds an actual value

What is register indirect addressing?

Address is stored in a register

What does MOV AX, [BX] do?

Loads into AX the value at the memory address in BX

What is the datapath in a CPU?

The hardware components that process data and perform operations

What is the Control Unit?

Directs datapath operations by generating control signals

What component performs arithmetic in the datapath?

ALU (Arithmetic Logic Unit)

What are the three main stages of instruction execution?

Fetch, Decode, Execute

Why do we use a memory hierarchy?

To balance speed, cost, and size of memory

What is the fastest memory type?

Registers

What type of memory stores active programs and data?

RAM (main memory)

What is cache memory?

A small, fast memory close to the CPU for frequently used data

What does DMA stand for?

Direct Memory Access

What is memory-mapped I/O?

I/O devices are accessed using normal memory instructions

What is polling in I/O?

CPU repeatedly checks device status

What's the benefit of interrupt-driven I/O?

CPU only acts when device signals readiness