Once attached to uCR, GDB knows about the threads of the application, can list them and can focus on any one of them at a time. Get a list of the threads with the info threads command, like so:
(uCR/i960) tar ucr /dev/cyclone0 (uCR/i960) info threads 2 thread 0x60044d50 0x60042278 in uCR_switch () * 1 thread 0x60045d50 0x60042278 in uCR_switch () (uCR/i960)
GDB numbers threads staring with 1, and displays the thread ID as uCR knows threads. The thread marked with a * is the current thread. Switch threads with a command like thread 2. The thread handling is a normal part of GDB.
Commands that examine registers or the procedure call stack always examine those of the current thread. Also, a thread that has faulted, either because of a TRACE or an actual fault, will be described at the point where it faulted. The fault handling code, which is normally on the thread stack, is not displayed by GDB.