Another question was two functions handling a queue implemented by a cyclic array. One function add to the queue and the other take from the queue and I have to follow the indexes for a given input. Then did told me there is a bug, it was something related to the order in which values are checked.

Given are two functions. One function writes to the shared memory using the function write_to_mem() One function reads from shared memory using the function read_from_mem() We also have a 8 bit variable sem. First function can set/clear only the first bit of sem (msb), indicating it just wrote to the mem. Second function can set/clear only the last bit of sem (lsb) indicating it finished reading from mem. Both functions can read both bits. The two functions might run on different processor with different frequencies. Processor 1 runs a code that call the first function in en endless loop Processor 2 runs a code that call the second function in en endless loop. I need to write the code in each processor such that the functions are synchronized.

We have a non volatile flash memory with the following properties: Page size is 400 bytes, in the beginning all pages are initialized to 1s It is only possible to set a 1 into 0, not possible to set 0 back to 1. It is possible to erase a page - setting all values to 1 After 1000 erase operations the page is damaged and finishes his life. You need to implement a counter with this flash memory and a RAM. The counter should be maintained such that if the computer is turned off unexpectedly and on again the counter should still be valid up to missing 1 or to counts.