Quiz submission record for quiz6-2-2 at Thu Jul 29 02:49:23 2004:

Your Answer for Question 1:
The EPC saves the address of the instruction that caused the exception.  The Cause register holds a field that indicates the reason for the exception.  lwc0,mfc0,mtc0,and swc0 access EPC and Cause.

Your Answer for Question 2:
When the correct exception is not always associated with the correct instruction in the pipeline that caused it.

Your Answer for Question 3:
It can waste a lot of processor time.

Your Answer for Question 4:
Memory-mapped IO means there is a special place in memory reserved for controlling interrupts.

loop: lb $t1,28(0xffff0000)
      or $t1,$t1,$0
      beqz $t1,end
      lb $t2,24(0xffff0004)
      add $v0,$t2,$0
      j loop
end:
     ... 


Your unique submission ID is quiz6-2-2-cs61c-at-1091094563-223.