Softx86 is a library that provides software emulation of an Intel 80x86 CPU. The library takes care of executing opcodes and handling exceptions while the host application is responsible for providing simulated RAM, I/O devices, external signals.
GNUDE is a complete suite of GNU C, C++, Fortran, and Java Cross Compilers, and the GDB CPUSimulator and Debugger for embedded microprocessor applications development. Targets development for ARM7, ARM9, and XScale applications.