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Contents

Microprocessors

8085 Architecture

8085 Architecture Overview 8085 Pin Description Timing Diagrams Control Signals Demultiplexing Bus

8085 Instructions

Addressing Modes Instruction Set Groups Stack Instructions Rotate Instructions 16-bit Arithmetic

8085 Programming

Assembly Language Basics Arithmetic Programs Looping and Indexing Stack and Subroutines BCD Arithmetic Time Delay Loops Code Conversion

8086 Architecture

8086 Architecture Memory Segmentation 8086 Pin Diagram Flag Register 8086 Instruction Queue

8086 Programming

8086 Addressing Modes 8086 Instruction Set String Instructions Interrupts DOS Function Calls BIOS Interrupts Macros vs Procedures Assembler Directives

Peripheral Interfacing

Memory Interfacing IO Interfacing 8255 PPI 8259 PIC 8253/54 Timer 8237 DMA 8251 USART 7 Segment Display Interface Stepper Motor Interface Keyboard Interfacing

Modern Processors

Evolution to Pentium Protected Mode Pipelining Cache Memory Virtual Memory Branch Prediction Multi-core Processors Hyper-Threading SIMD Instructions

Other Topics

RISC vs CISC Microcontroller Difference Bus Standards

Other Subjects

Analog Electronics Digital Electronics Signals & Systems Control Systems Electromagnetic Theory Digital Communication Analog Communication Network Analysis VLSI Design Verilog HDL Power Electronics Embedded Systems DSP Electronic Devices

Section Progress22%

2 of 9 articles

Protected Mode

Descriptor tables, selectors, protection rings.

Updated: 19 March 2026

10 min read

#Microprocessors

Protected Mode Quiz

Test your understanding of x86 protected mode, descriptor tables, selectors, and privilege rings.

Question 1 of 3

Q1.In x86 protected mode, a segment selector stored in a segment register contains a 13-bit index, a TI bit, and a 2-bit RPL field. What does the TI bit specify?

Related Articles

Multi-core Processors

SMP, CMP, shared memory consistency.

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Hyper-Threading

SMT concepts.

4 min read

Virtual Memory

Paging, segmentation with paging, TLB.

5 min read

SIMD Instructions

MMX, SSE, AVX overview.

12 min read

Branch Prediction

Static and dynamic prediction methods.

4 min read

Evolution to Pentium