Quiz submission record for quiz6-2-2 at Thu Jul 29 10:13:24 2004:

Your Answer for Question 1:
EPC register holds the instruction address of whatever caused the exception. The Cause register holds an address that indicates to the OS the nature of the exception. Any instruction that is undefined or causes problems access EPC and Cause; arithmetic instructions that cause overflow or problems in memory access can access those registers.

Your Answer for Question 2:
Imprecise exceptions are those which don't specify exactly where the exception occured to make the hardware a bit simpler, leaving it to the OS to decipher which instruction caused the exception.

Your Answer for Question 3:
IO devices might not be able to keep up with polling by the processor and might waste a lot of CPU time.

Your Answer for Question 4:
Memory-mapped IO means that there are specific locations in memory that are used to hold instructions/data for IO devices. 

loop:
andi $t0, $a0, 0x0001
beq $t0, $0, loop
lb  $v0, 0($a1)


Your unique submission ID is quiz6-2-2-cs61c-eq-1091121204-1509.