Emu8086!

i8086emu is an cross-platform emulator for the Intel 8086 microprocessor. It has support for dynamically loadable device plugins and some peripherals like a PIT, PIC, 8-segment-displays, buttons and leds. i8086emu comes with an ncurses and an GTK-2 gui.It is basically designed for emulating a Single Board Computer 86 (SBC86) which is used in our microprocessor faculty. For this reason it consists of the original ROM of the SBC86 which is a whole debug-software with extra trace and step functionality.This piece of software is published under the GPL and therefore marked as open source. »

The Netwide Assembler, NASM, is an 80x86 and x86-64 assembler designed for portability and modularity. It supports a range of object file formats, including Linux and *BSD a.out, ELF, COFF, Mach-O, Microsoft 16-bit OBJ, Win32 and Win64. It will also output plain binary files. Its syntax is designed to be simple and easy to understand, similar to Intel's but less complex. It supports all currently known x86 architectural extensions, and has strong support for macros.

The flat assembler is a fast and efficient self-assembling x86 assembler for DOS, Windows and Linux operating systems. Currently it supports x86 and x86-64 instructions sets with MMX, 3DNow!, SSE up to SSE4, AVX, AVX2 and XOP extensions, can produce output in plain binary, MZ, PE, COFF or ELF format. It includes the powerful but easy to use macroinstruction support and does multiple passes to optimize the instruction codes for size. The flat assembler is self-compilable and the complete source code is included. »

PCem offers emulation of various IBM PC compatible machines, from the original 1981 model 5150 to later successors and clones by third party manufacturers. The software includes emulation of several compatible graphical video adapters, audio devices, and other peripherals of the day.

Here you can find the original version of David Hedley's 8086 PC emulator, and my "improved" version. This will emulate a basic PC with a VGA text-only display quite well; there is a reasonable amount of software that will work with no problems. The emulator uses the mfs.c code from Linux DOSEMU to mount Unix directories as drives under DOS, so you can transfer data from the host to the target easily. The improved version supports EMS memory and quite good floppy drive support.