Emu8086 is a proprietary microprocessor emulator and assembler software that allows users to write, test, and run assembly language programs for the Intel 8086 microprocessor on a computer. It provides a simulated environment for programming and testing 8086-based applications without the need for physical hardware.

The emu8086.inc file is a header file that contains macros definitions used by the Emu8086 assembler. It is included in assembly language programs written for the Emu8086 emulator to provide access to the emulator's functionality and to simplify programming. The file includes definitions for printing and gathering strings and numbers as input/output.

You can find its documentation in Emu8086's docs: Tutorial part 5: library of common functions - emu8086.inc

Emu8086 uses its own assembler which is not FASM syntax-compatible because the Emu8086 assembler is designed to work specifically with the Emu8086 emulator. The syntax and structure of the Emu8086 assembler are tailored to the features and functionality of the emulator, which may differ from those of other assemblers like FASM. Even though you can add the #fasm# directive to make Emu8086 use FASM, emu8086.inc is not FASM-compatible. Therefore, I modified the code written in emu8086.inc to work with the FASM syntax.

Just import it in your code using the include directive:

include 'emu8086.inc'

Then build it with fasm:

fasm example.asm example.com

You may use DOSBox to run your 8086 programs.

Under the examples/ directory you will find example programs tested in DOSBox. These were also tested in Emu8086, just remove brackets ([ ]) in variables to work with the Emu8086 syntax.

So, I was studying a computer architecture course at my university and we were learning 8086 assembly with Emu8086. However, Emu8086 is Windows-only, proprietary and couldn't make it work with Wine. This led me to learn assembly with NASM/FASM and DOSBox, but due to the fact that emu8086.inc macros made life so much easier, I decided to "port it" to FASM.