EasyCPU is a free, browser-based Intel 8086 assembly language simulator and debugger. It lets you write, assemble, and execute 8086 assembly programs with a visual interface showing CPU registers, flags, memory, stack, LEDs, 7-segment displays, a pixel screen, and a VT100 text terminal.

How do I learn 8086 assembly language?

EasyCPU provides a beginner-friendly environment to learn 8086 assembly. Start with the built-in sample programs, use the step-by-step debugger to see how each instruction changes registers and memory, and try the auto-graded coding challenges to test your skills.

Is EasyCPU free to use?

Yes, EasyCPU is completely free. It runs entirely in your web browser with no installation, signup, or download required.

EasyCPU - Free Online 8086 Assembly Simulator & Debugger

EasyCPU is a free, browser-based Intel 8086 assembly language simulator and debugger. Write, assemble, debug, and run 8086 assembly programs directly in your browser — no installation required.

Features

8086 Assembly Code Editor with syntax highlighting and autocomplete
Step-by-step debugger with breakpoints and execution trace
Visual CPU register display (AX, BX, CX, DX, SP, BP, SI, DI, IP, DS, SS, CS)
CPU flags viewer (CF, ZF, SF, OF, PF, AF)
Memory viewer with hex dump
Stack viewer
LED output display (8 LEDs via Port 2)
7-segment display (Port 3)
32x32 pixel display (Port 4)
VT100 text terminal (Port 8 / INT 21h)
Keyboard input buffer (Port 5/6)
I/O port simulation
Sample programs library for learning
Coding challenges with automatic grading
Number converter (Hexadecimal, Decimal, Binary)
Beginner and Advanced modes
Save, load, and download assembly programs

Learn 8086 Assembly Language

EasyCPU supports a wide range of Intel 8086 instructions including MOV, ADD, SUB, MUL, DIV, AND, OR, XOR, NOT, CMP, JMP, JE, JNE, JG, JL, PUSH, POP, CALL, RET, INT, IN, OUT, LOOP, and many more. Perfect for students learning computer architecture, microprocessor programming, and low-level assembly language.

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Code Editor

VT100 Terminal (Port 8)

Click the screen to type. OUT 8 / INT 21h AH=09h print here.

Registers

AX0000AH00AL00

BX0000BH00BL00

CX0000CH00CL00

DX0000DH00DL00

SP0100

BP0000

SI0000

DI0000

IP0000

DS0000

SS0000

CS0000

Flags

CF0

ZF0

SF0

OF0

PF0

AF0

LED Output (Port 2)

7

6

5

4

3

2

1

0

Value: 00h (0)

7-Seg Display (Port 3)

Value: 0

I/O Ports

Input Port 1: hex (00-FF)

Number Converter

Hex:

Dec:

Bin:

Keyboard (Port 5/6)

Buffer: (empty)

Stack

Pixel Display (Port 4)

Challenges

Memory Viewer

Go to: Segment:

Trace Log

#	IP	Instr	AX	BX	CX	DX	Flags

Output Console

EasyCPU Help Guide