Question 7 (2 points)

Lets say you want to write a program for comparing two strings. You have a choice of using a 32-bit byte-addressable Big-endian or Little-endian architecture to do this. In either case, you can pack 4 characters in each word of 32-bits. Which one would you choose?

Question 7 options:

	It must be Big-endian
	It must be Little-endian
	Either one works as long as you are consistent in the comparison.
	Neither one works.

Question 8 (2 points)

Given the following load instruction

LW Rx, Ry, OFFSET ; Rx <- MEM[Ry + OFFSET]

Show how to realize a new addressing mode, called indirect, for use with the load instruction that is represented in assembly language as:

LW Rx, @(Ry) ;

Question 8 options:

	LW Rx, Ry, 0 LW Rx, Rx, 0
	LW Rx, Rx, 0 LW Ry, Rx, 0
	ADD Rx, Ry, 0 LW Ry, Rx, 1
	LW Rx, Ry, 0 LW Ry, Ry, 0

Question 9 (2 points)

Instruction "ld r1, 3(r2)" can do memory accessing. the semantics of this instruction is _________

Question 9 options:

	The content in the memory cell addressed by "r1+3" is fetched and placed in register "r2".
	The content in the memory cell addressed by "r2" is fetched and placed in register "r1".
	The content in the memory cell addressed by "r2+3" is fetched and placed in register "r1".
	The content in the memory cell addressed by "r2" is fetched and placed in register "r1+3".

Question 10 (2 points)

Consider the following array in memory with each element occupying four memory cells.

int a[100]

The starting memory address for this array is 2000. What is the starting address for element a[8]?

Question 10 options:

	2000
	2028
	2032
	2008

Question 11 (2 points)

Consider the following code, please point out the value of z after executing the code.

x=10; y=20; z=0;

if (x==y) z=8;

else z =15;

Question 11 options:

	0
	8
	15
	21

Question 12 (2 points)

_____ contains the first address on the stack that pertains to the activation record of the called procedure and never changes while this procedure is in execution.

Question 12 options:

	stack pointer
	frame pointer
	program pointer
	program counter

Question 13 (2 points)

Intel X86 is __________ architecture style.

Question 13 options:

	stack oriented
	memory oriented
	register oriented
	hybrid of memory-oriented and register-oriented

Question 14 (2 points)

________________ instructions are easy to implement, but waste space.

Question 14 options:

	Fixed length
	Variable length
	Both fixed length and variable length
	Neither fixed length nor variable length

Question 15 (2 points)

Consider the following high-level language code, which one is its assembly code implementation?

while(i ! = 0)

{

/* loop body */

t = t + b[i--];

}

Question 15 options:

	be r1, r0, done; loop body .... done: ....
	beq r1, r0, done; loop body .... done: ....
	beq r1, r0, loop body; loop body .... done: ....
	beq r1, r1, done; loop body .... done: ....

Question 16 (2 points)

The following assembly code implements _____ statement.

beq r1, r2, then

add r3, r6, r7

beq r1, r1, skip

then add r3, r4, r5

skip

Question 16 options:

	if
	if ... else
	switch
	while

Question 17 (2 points)

Activation record is not used to store ________

Question 17 options:

	caller saved register
	program counter
	return address
	local variables

Question 18 (2 points)

Work out the details of implementing the switch statement using jump tables in assembly using any flavor of conditional branch instruction. The correct order is _______________.

1) Execute the desired branch

2) Continue with your original code

3) check the bounds of the switch variable

4) JLR or JMP $return_address

5) If the variable is within the bounds, you would index into the jump-table based on which switch case was executed.

Question 18 options:

	3) 5) 1) 4) 2)
	3) 1) 4) 2) 5)
	5) 1) 2) 3) 4)
	3) 2) 5) 1) 4)

Question 19 (2 points)

Consider the usage of the stack abstraction in executing procedure calls. The amount of memory included in the stack at any given time is controlled by simply changing the _____ pointer value.

Question 19 options:

	program
	frame
	stack
	memory

Question 20 (2 points)

Upon an interruption, which action is completed not by hardware?

Question 20 options:

	save processor registers
	save program counter
	detect address of interrupt handler
	disable interrupt

Question 21 (2 points)

The reason that we do not use JALR to return from the interrupt handler is __________.

Question 21 options:

	After enable interrupts and JALR $k0, it may get a new interrupt that will trash $k0.
	In between enable interrupts and JALR $k0, it may get a new interrupt that will trash $k0.
	In between enable interrupts and JALR $k0, it may not get a new interrupt that will kill $k0.
	Before enable interrupts and JALR $k0, it may get a new interrupt that will change the value in $k0.