For testing Nintendo 64 homebrew ROMs, cen64 is the most accurate emulator (though it doesn't run at full speed yet). Here's how to build it from source on macOS:

1. Install XQuartz from the official distributed disk image
2. brew install cmake glew
3. git clone https://github.com/n64dev/cen64.git
4. cd cen64
5. mkdir build
6. cd build
7. cmake ..
8. make

If you'd like to enable cen64's debug logging, create a debug build when running cmake:

cmake -DCMAKE_BUILD_TYPE=Debug ..

When running cen64 outside of an XQuartz X11 terminal, it may report:

Using NTSC-U PIFROM
create_device: Failed to initialize the VI.
Failed to create a device.

To fix this, you can run it within an XQuartz X11 terminal, or set the DISPLAY environment variable to something like :0 either in your .bashrc file or inline during invocation:

DISPLAY=:0 ./cen64 /path/to/pifdata.bin /path/to/rom.z64

DISPLAY needs to be set because cen64 calls XOpenDisplay with a NULL display name (presumably to default to your DISPLAY environment variable), but if it's not set, XOpenDisplay returns NULL and cen64 has no display within which to create a window for rendering Nintendo 64 content.

For extremely verbose register-level output, edit CMakeLists.txt and set DEBUG_MMIO_REGISTER_ACCESS to ON. Make sure to remove any cached data in build/ to ensure your changes are reflected, then recompile and re-run.

Update 2024-03-02

Development on cen64 has not progressed in many months and is now considered unmaintained. ares, a cross-platform, open source, multi-system emulator is now regarded as the best emulator for Nintendo 64 development.