DOS Debug Commands

Before we shift to assembly language programming, we will learn a bit about DOS debug commands.

DOS (Disk Operating System) helps us in debugging...

I would be putting up a video lecture for DOS Debug Commands..

Next Step

So, these were the basic instructions of the microprocessor instruction set of the x86 family..

There are about 20,000 instructions in the instruction set, I would share with you the rest of instructions but firstly  we would have a quick overview of the Assembler Directives..

What is an  Assembler..? What is the use of it.? And why do we need an assembler..?

• An assembly language is a low-level programming language for computers, microprocessors, micro-controllers and other programmable devices. 

• A utility program called an assembler is used to translate assembly language statements into the target computer's machine code.
• The assembler performs a more or less isomorphic translation (a one-to-one mapping) from mnemonic statements into machine instructions and data. This is in contrast with high-level languages in which a single statement generally results in many machine instructions.

• We would be using a Turbo Assembler TASM in short. You could find it on the Google

Processor Control Instruction


 These instructions control the processor itself.
 8086 allows to control certain control flags that:
 causes the processing in a certain direction
 processor synchronization if more than one microprocessor attached.

String Instructions

String Instructions



 String in assembly language is just a sequentially
stored bytes or words.
 There are very strong set of string instructions in 8086.
 By using these string instructions, the size of the
program is considerably reduced.

Program Execution Transfer Instructions

 These instructions cause change in the sequence of the
execution of instruction.
 This change can be through a condition or sometimes
unconditional.
 The conditions are represented by flags.

Bit Manipulation Instructions

 These instructions are used at the bit level.
 These instructions can be used for:
 Testing a zero bit
 Set or reset a bit
 Shift bits across registers

Data Transfer Instructions

 These instructions are used to transfer data
from source to destination.

 The operand can be a constant, memory
location, register or I/O port address.

Instruction Set of 8086

 An instruction is a binary pattern designed
inside a microprocessor to perform a specific
function.
 The entire group of instructions that a
microprocessor supports is called
Instruction Set.
 8086 has more than 20,000 instructions.


The instructions of 8086 are classified into SIX groups. They are:

• DATA TRANSFER INSTRUCTIONS
• ARITHMETIC INSTRUCTIONS
• BIT MANIPULATION INSTRUCTIONS
• STRING INSTRUCTIONS
• PROGRAM EXECUTION TRANSFER INSTRUCTIONS
• PROCESS CONTROL INSTRUCTIONS

Welcome

Welcome friends..

This is another blog related to the microprocessors of Intel.. An Instruction Set of any microprocessor is quite important to learn as a programmer point of view.. I'm here to share my knowledge of 80x86 processors..

I would appreciate your contribution in making this portal better and useful for the beginners as well as experienced.. So do inform any correction which I need to make..