The "Open On-Chip Debugger" provides JTAG/SWD access from GDB (or directly with TCL scripts) to processors with ARM and MIPS based cores.
See website for full list of supported targets.
MEDDAC is the seeding point for designing a new approach to Operating System design itself. It is an Open Source project with roots in mainframe design and development the author began in 1979. Monitor Editor Disassembler Decompiler Assembler Compiler