



Computer Systems
eXercise #4
BITs and BYTES
Note: V=OR, &=AND, ~=NOT
 If A=TRUE, B= TRUE and C=FALSE, evaluate the following:
 A & B
 A V C
 (A & ~B) V C
 ~(A & B) & (A & C)
 A & (~A V B) V (~C V ~B) & C
 If P=10111111, Q=10101010 and R=11110000, evaluate the following:
 P & Q
 P V R
 (P & ~Q) V R
 ~(P & Q) & (P & R)
 P & (~P V Q) V (~R V ~Q) & R
 Regarding the SIGNED INTEGER 9063
 Express it in TWO'S COMPLIMENT form
 Perform a SHL3 on part 1's answer, and explain the result
 Perform a SHR5 on part 1's answer, and explain the result
 What would the answer to the following sum (without converting
it to binary) 9063 &~9063
 Regarding Software and Hardware Interrupts
 Wht are they PRIORITIZED prior to being noticed by the CPU?
 Explain the purpose of the Interupt Vector Table
 Describe the actions resulting from the receipt of 2 high priority
interupts within a short interval of each other (supposing the
interval is not sufficiently long to completely deal with the
first interupt before the next, higher priority one comes along)
 Determine the results of the following:
 not 255
 27 or 45
 255 and 3
 Suppose we decide to encode a calendar date into BINARY using the
following scheme:
YYYYYYYMMMMDDDDD
eg. 1100001101111101
97 11 29 = 29th November, 1997
 Supposing I wished to ISOLATE just the month in a 2 BYTE WORD,
what logical operations would be necessary to achieve this?
 What logical operations would be necessary to determine if the
YEAR was 1998?






