Adaface Sample Embedded Systems Questions

Consider the following logic box. There are three inputs A, B, C and three outputs not A, not B and not C (not A = !A, not B = !B, not C = !C).
            
            Is it possible to achieve the expected outputs from the inputs using:
            
            - Only AND and OR gates
            - Just two (2) NOT gates
            - No NAND, NOR, XOR, or XNOR gates

Review the following Embedded Systems code and memory map of 16-bit microcontroller:

Here are the specifications of the microcontroller:
            
            - The stack grows from area D, whereas the program and static variables are stored in area C
            - ‘int’ in the system is a 16-bit number
            - There is no operating system and no memory protection
            - The program is compiled and loaded into area C

Pick the correct statements:
            
            A: first_var, second_var and input will be in area D
            B: first_var and second_var will be in area C, input will be in area D
            C: If the contents of 0x0010 at the start of the program is 7, the program will print 0 and exit
            D: If the contents of 0x0010 at the start of the program is 42, the program will print 0 and exit
            E: If the contents of 0x0010 at the start of the program is 42, the program will overflow the stack overwriting the program and static variables region
            F: If the program overflows and overwrites the program and static variables region, arbitrary data is executed as if it is the program, causing unpredictable results

Review the following Embedded Systems code:

Here’s the specification for the program:
            - first_var and second_var are global variables shared among several threads
            - first_lock and second_lock are mutex locks that protect access to first_var and second_var
            - Reads and writes to variables first_var and second_var are not guaranteed to be atomic
            - No locks must be acquired unnecessarily
            - Acquire second_var lock first before acquiring first_var lock by any thread that is going to use both first_var and second_var

Assume that if a thread attempts to acquire a lock it already holds, then it is immediately granted the lock. Pick the correct statements:
            
            A: The provided code does not meet the specification completely since second_lock is not acquired before acquiring first_lock for procedure 'foo'
            
            B: Replacing foo with logic of foo1 makes sure locks are not acquired unnecessarily and  second_lock is acquired before acquiring first_lock
            
            C: Replacing foo with logic of foo1 makes sure second_lock is acquired before acquiring first_lock but there are cases when second_lock is acquired unnecessarily (when first_var < input)
            
            D: Replacing foo with logic of foo2 makes sure locks are not acquired unnecessarily
            
            E: Replacing foo with logic of foo2 is optimized version of foo1 but there are cases when second_lock is still acquired unnecessarily (when first_var value changes from the time ‘res’ value is computed and by the first_lock is acquired again.