# Midterm #2 -- closed book section

12 April, 1994

The entire exam is to be turned in at 2:55 PM. Work the closed
book section first and turn it in before you consult your books and
notes to work on the open book section.

## Problem 1. (6 points)

If the binary representation for 165 is 10100101 and the binary
representation for 1994 is 11111001010, what is the twelve-bit
signed-2's complement binary representation of -165 and -1994?

## Problem 2. (6 points)

How is overflow detected when two signed-2's complement numbers
are added?

## Problem 3. (12 points)

In a paragraph or two, describe how a DMA controller oversees
the transfer of data from an I/O device to memory.

## Problem 4. (6 points)

Would you expect the first bit of the exponent field of the
floating point number representing 1994 to be zero or one in a
processor, such as the Alpha AXP or the MIPS R3000, that uses
biased exponents. Explain your answer.