Classification of Instructions set

Data Movement Instructions

Instructions	Definition/Meaning
MOV	Transfer data from source to destination.
XCHG	Swap the contents of two registers or a register and a memory location.
PUSH	Push data onto the stack.
POP	Pop the data from the stack.
LEA	Load Effective Address (loads the address of a memory operand into a register).

Arithmetic Instructions

Instructions	Definition/Meaning
ADD, SUB, ADC, SBB	Sum, difference, sum with carry, difference with borrow.
INC, DEC:	Increment, decrement.
MUL, IMUL, DIV, IDIV:	Multiplication and division (unsigned and signed).

Logic Instructions

Instructions	Definition/Meaning
AND, OR, XOR, NOT	Bitwise logical operations.
TEST	Bitwise AND operation modifies flags while operands remain unchanged.
SHL, SHR, SAL, SAR	Shift left, shift right (logical and arithmetic).
ROL, ROR, RCL, RCR	Left rotate, right rotate (with carry).

Control Transfer Instructions

Instructions	Definition/Meaning
JMP	Absolute jump to a specified address.
JC, JNC, JZ, JNZ, JS, JNS, JO, JNO	Conditional branching on the flags.
CAL	Call a subroutine.
RET	Return from subroutine.
INT	Software interrupt.
IRET	Interrupt return.

String Instructions

Instructions	Definition/Meaning
MOVSB, MOVSW	Transfer byte or word from source to destination (used in string manipulation).
CMPSB, CMPSW:	Compare byte or word string operands.
SCASB, SCASW	Scan byte or word string operands.
LODSB, LODSW	Get a byte or word from memory into the accumulator.

Input/Output Instructions

Instructions	Definition/Meaning
IN	Input from port.
OUT	Output to port.

Flag Control Instructions

Instructions	Definition/Meaning
CLC, STC, CMC	Set, clear, complement flags on CY.
CLD, STD	Set direction flag.
CLI, STI	Clr int flag.
HLT:	Halt processor execution.

Other Instructions

Instructions	Definition/Meaning
NOP	No operation.
WAIT	Await external event.
ESC	Jump to external coprocessor.

Process Control Instructions

Process Control Instructions are used to control the order execution in a program and in processes. They comprise of instruction for branching, looping, and calling functions or subroutines.

In other words, the instruction set changes the sequence of instruction executing, therefore, it allows to change the program flow. Include commands for conditional jump, unconditional jump, subroutine calls among others.

Instruction	Definition/Meaning
Branching Instructions	Branching Instruction that transfers the flow of execution onto certain conditions or unconditional transfers to the part of the program.
Looping Instructions	Instruction that can be used to repeatedly execute a block of code either conditionally or unconditionally.
Subroutine Instructions	Subroutine Instructions are used to call and return from subroutine to enhance code modularity and reusability.
Unconditional Jumps	Unconditional Jumps Included in the program flow are the instructions that unconditionally jump to a predetermined location without taking any condition in to account.
Conditional Jumps	Conditional Jumps Conditionals that moves the control flow to a specific address depending on the truth value of a condition.
Subroutine Calls	Jump Commands Instructions that are responsible for transferring control to a subroutine, enabling task execution, while promoting code modularity and reusability.

8086 Instruction Set

The 8086 instruction set is key to understanding the Intel 80 coding pattern and its significant significance as a path-making chip among x patterns. Unveiled in 1978, it brought innovation into computing by having the ability to provide better overall performance and memory attributes than earlier devices. This article investigates the details behind the 8086 instruction set as well its additives of it in matters of class, addressing modes key command and assembly language programming extensions complexes regarding challenges and further advantages.

Table of Content

8086 Instruction Set
Classification of Instructions set
Addressing Modes
Key Instructions in the 8086 Instruction Set
Assembly Language Programming with the 8086
8086 Instruction Set Extensions
FAQs on 8086 Instruction Set