These are the tools that I'm using to develop my custom UNIX like Data General Nova operating system: NOVIX
The tools incluse:
dgnasm - The Data General Nova Assembler
dgnmcc - The Data General Nova Micro C Compiler
dgnirc - The Data General Nova Intermediate Representation Compiler
dgndbg - The Data General Nova Symbolic Debugger
dgnlnk - The Data General Nova Dynamic Linker