UPS is a source level C, C++ and Fortran debugger with an X windows interface. It's a very light debugger, but is quite efficient and works well. An ANSI compliant C interpreter is included.
GNUDE is a complete suite of GNU C, C++, Fortran, and Java Cross Compilers, and the GDB CPU Simulator and Debugger for embedded microprocessor applications development. Targets development for ARM7, ARM9, and XScale applications.