CS 33 S23 Final Trial by Fire

What is hex 0xB6 in decimal?

• 182

• 163

• 192

• 136

A is an object of type foo. What does the memory at A look like when the following code is run?

• 00 00 00 00 64 44 01 02

• 01 02 00 00 00 00 00 00

• 02 01 c0 00 00 00 00 00

• 00 00 00 00 00 c0 01 02

For a floating point number, what would be an effect of allocating more bits to the exponent part by taking them from the fraction part?

• You could represent fewer numbers, but they could be much larger.

• You could represent the same numbers, but with more decimal places.

• You could represent both larger and smaller numbers, but with less precision.

• Some previously representable numbers would now round to infinity.

Which of these can prevent an ROP attack?

• Set random values on the stack and check them to make sure they’re unchanged

• Set stack as read-only by setting the correct bits in the process’s page table

• Address space layout randomization– randomly move the starting address of the stack

• Checking that the user input will not overwrite the amount of buffer space allocated for it

What is add %rsi, (%rax) in MIPS? Assume rsi == t0 and rax == t1.

• add $t0, ($t1)

• 1. lw $t1, 0($t1)

  2. add $t0, $t0, $t1 

• lw $t1, ($t0)

  add $t1, $t0, $t1

• add $t0, ($t1), $t0

When a program tries to access a page that is mapped in address space but not loaded in physical memory, then

• Segmentation fault

• Page fault

• No issue - proceed as usual

• Context switch

What is the order in which preprocess flow happens?

• Compile, Preprocess, Link

• Compile, Link, Preprocess

• Preprocess, Link, Compile

• Preprocess, Compile, Link

Which of these are the fastest access time?

• L1 cache

• Register memory

• TLB

• Main memory

What is the difference between a trap and a fault?

• A trap is an exception, while a fault is not

• A trap is intentional, while a fault is not

• A trap is recoverable, while a fault is not

• A trap is synchronous, while a fault is not

When you print the address of a variable from C, what kind of address is that?

• Physical Address

• Virtual Address

• Depends on the context