There seems to be a lot of discussion online about the development hardware used to create Nintendo 64 titles: SGI Indy "pizza box" workstations, SGI's custom Ultra 64 development boards (aka "DEVELOPMNET" boards), and testing using a modified Sega Saturn controller before the N64 controller specs had been completed. But I can't find too much information about the development software used on these machines. Was it custom built by SGI? Was it similar to tools like CodeWarrior or C++ Builder?
It used the same C compiler that shipped with the Indy workstation. See: Nintendo 64 Development Manual: C Compiler Suite
It required a few flags not normally used when building C programs for the Indy itself. And there were utilities for downloading to the development boards and converting executables into ROM images.
Some IDE's were available for UNIX at the time, but Nintendo didn't provide anything beyond system libraries and starter makefiles for the venerable "make" build command. I'd expect most developers built N64 games in the same way they did Unix programs. Run "make" on the command line and correct any errors in a separate editor window. Or possible run "make" on a command line inside the emacs text editor with macros to assist in locating errors.
gvd for debugging programs that were downloaded using
gload. It appears that it was similar in function to typical Unix command line debuggers like
A comment mentions
libultra. It is a C library of various utility functions ranging from common C library functions like
abs() to matrix math, hardware accessors, threading primitives and so on. The documentation has a complete list of functions. At the bottom of the page are links to functions grouped by category.