8086 emulator alternative: see the hardware an emulator imitates
The Intel 8086 is the 16-bit processor that started the x86 family. One free option today is the open-source 8086 Emulator by Yashodhan Joshi and colleagues: a Rust interpreter, compiled to WebAssembly for a browser version at yjdoc2.github.io/8086-emulator-web and also available as a command-line program (Apache 2.0 license). Its README says it runs most of the 8086 instruction set with 1 MB of emulated memory, executes the assembly with an interpreter rather than storing the code in memory, and therefore allows jumps only to labels, supports only selected interrupts and does not emulate external devices. The web version runs a program all at once or line by line and shows the registers and flags as it goes. An 8086 emulator runs x86 programs on an imitation of the chip; digiwleea has you build a processor's hardware yourself, gate by gate.
What an online 8086 emulator is good at
Practising 8086 assembly for a microprocessors course with nothing to install: write a program, step through it line by line, and watch AX, BX, the flags and memory change. For the classic MOV, ADD and loop exercises, a browser emulator is the quickest way to check your work. (digiwleea is an independent project, not affiliated with the 8086 Emulator project or Intel.)
How digiwleea is different
digiwleea does not emulate the 8086 or run x86 code. It shows what an emulator imitates: in the browser you build NOT and NAND from CMOS transistors, then adders, an ALU, registers, RAM, a program counter, an instruction register and a control unit, through a 40+ level course where every part is checked against its truth table, with an AI tutor (Wleea). The CPU you finish with is far smaller than an 8086: an 8-bit accumulator machine whose capstone runs a stored LOAD, ADD, STORE, HALT program, with the parts for SUB, JMP, JZ and OUT built in Act IV. What you gain is the view from inside: what a register, a flag or the decoding of an opcode is made of.
| 8086 emulators | digiwleea | |
|---|---|---|
| Focus | Running 8086 assembly | Digital logic from transistors to a simple CPU |
| The CPU | An imitation of the 8086's registers and flags | Built by you: a small 8-bit accumulator machine |
| Runs on | Browser (WebAssembly) or command line | Any modern browser |
| Limits | No jumps to memory positions, selected interrupts, no devices | No x86 at all: its own tiny instruction set |
| Price | Free, open source (Apache 2.0) | Free lab and Act I; Premium for the full course |
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
More comparisons: CPU and assembly simulators
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
Is there a free online 8086 emulator?
Yes. The open-source 8086 Emulator has a browser version at yjdoc2.github.io/8086-emulator-web that runs most of the 8086 instruction set line by line, showing registers and flags.
What are the limits of an interpreter-based 8086 emulator?
The 8086 Emulator's README notes that because code is interpreted rather than stored in its 1 MB memory, jumps must go to labels, only selected interrupts work, and external devices are not emulated.
Can I build an 8086 in digiwleea?
Not as a finished chip. digiwleea's course builds a smaller 8-bit accumulator CPU from transistors up, and the lab lets you build the kinds of parts an 8086 contains: registers, an ALU, decoders and a program counter.