Answer from cs61c-ck (Allen Lee 16583554) for Question 1
The EPC (exception program counter) register holds the address of the instruction that caused an exception.  The Cause register holds information about the cause of the exception; its lower order bit indicates whether the exception was caused by an undefined instruction (0) or arithmetic overflow (1).  The EPC and Cause registers are located in coprocessor 0, so they can be accessed using mfc0 (move from coprocessor 0).