The GameShop debugger (gvd) originiated from the Silicon Graphics WorkShop application development tools. It is a source level windowing debugger environment that enables debugging of both the CPU and RSP software.
The debugger is actually composed of several different components shown in Figure 4-5, below.
There are two debugging paths. The first path is a C source level windowing debugger, gvd, which has most of the features of common multi-threaded debuggers. In this path the debugger sends a message to dbgif and dbgif passes the received message to the rmon debug thread through the Nintendo 64 device driver in IRIX.
The second path is the popular printf traces within the application. rmonPrintf() displays the messages in the shell that executed dbgif.
![[Figure 4-5]](gif/f04-05.gif)
The rmon debugger thread is actually a high-priority thread in the game application and uses many operating system resources. Therefore, the GameShop debugger and rmonPrintf function cannot be used to debug system-level code.