MenuDesigner is a small GUI system for monochrome LCDs suitable for embedded systems with very limited system resources (like 8 Bit microcontrollers). Comes with a graphical editor for creating a menu.

Platform: OS Portable (Source code to work with many OS platforms);

License: GNU General Public License (GPL)

Reference：https://menudesigner.sourceforge.net

Softgun is an ARM (and other CPU) emulator. It is Intended to help developers of embedded systems without real Hardware. Currently it emulates an ARM-9 in Netsilicon, Freescale and Atmel CPUs. Also the Atmel ATMega644 is emulated

Platform: All POSIX (Linux/BSD/UNIX-like OSes), Linux;License: BSD License, GNU General Public License (GPL)

Reference：https://softgun.sourceforge.net

Bochs is a highly portable open source IA-32 (x86) PC emulator written in C++, that runs on most popular platforms. It includes emulation of the Intel x86 CPU, common I/O devices, and a custom BIOS. Currently, Bochs can be compiled to emulate a 386, 486, Pentium/PentiumII/PentiumIII/Pentium4 or x86-64 CPU including optional MMX, SSEx and 3DNow! instructions.

Platform: OS Portable (Source code to work with many OS platforms);   License: LGPL

References: https://bochs.sourceforge.net/

ProEmulator is a retargetable embedded system emulator architecture, providing common support to emulate various types of micro-processors & devices on an x86 PC (Linux or Windows). PEMU is an emulation engine on which ProEmulator runs. It is OS independent and currently runs on Linux and Windows. A flexible and portable plug-in architecture is designed, which abstracted micro-processors and some devices and provides a common interface. This enables emulating a new processor or device in PEMU/ProEmulator easier than starting from scratch. PEMU provides user with a command line interface (similar with that of GDB). ProEmulator is actually PEMU plus a nice GUI. This GUI currently only runs on Windows and is developed with Win32 SDK.

Platform: All 32-bit MS Windows (95/98/NT/2000/XP), Linux, MinGW/MSYS (MS Windows);   License: GPL

References: https://proemulator.sourceforge.net/