OSAssignment4

Memory Allocation

Task

Using C++, create a memory management unit simulator that will implement dynamic storage allocation using paging. The page size will be determined based on a command line parameter, but must be a power of 2 (between 1024 and 32768). You will not actually be spawning processes that consume memory. Rather you will be creating simulated "processes" that each make a series of memory allocations and deallocations. The following are the actions that a process can do:

• Initialize
  • Assign a PID - unique number (start at 1024 and increment up)
  • Allocate some amount of startup memory for the process
    • Text/Code: user specified number (2048 - 16384 bytes)
    • Data/Globals: user specified number (0 - 1024 bytes)
    • Stack: constant (65536 bytes)
• Allocate memory on the heap
  • N chars (N bytes)
  • N shorts (N * 2 bytes)
  • N ints / floats (N * 4 bytes)
  • N longs / doubles (N * 8 bytes)
• Set value for allocated memory
  • Store integer, float, or character values in memory
• Deallocate memory from the heap
  • N chars (N bytes)
  • N shorts (N * 2 bytes)
  • N ints / floats (N * 4 bytes)
  • N longs / doubles (N * 8 bytes)
• Terminate
  • Deallocate all memory associated with the process

Your simulator should continually ask the user to input a command. Your program should interpret the following statements:

• create <text_size> <data_size>
  • Initializes a new process
  • Prints the PID
• allocate PID <var_name> <data_type> <number_of_elements>
  • Allocated memory on the heap (how much depends on the data type and the number of elements)
  • Print the virtual memory address
• set PID <var_name> <value_0> <value_1> <value_2> ... <value_N>
  • Set the value for variable <var_name> starting at
  • Multiple contiguous values can be set with one command
• free PID <var_name>
  • Deallocate memory on the heap that is associated with <var_name>
• terminate PID
  • Kill the specified process
• print
  • If is "mmu", print the MMU memory table
  • If is "page", print the page table (do not need to print anything for free frames)
  • If is "processes", print a list of PIDs for processes that are still running
  • If is a "PID:<var_name>", print the value of the variable for that process
    • If variable has more than 4 elements, just print the first 4 followed by "... [N items]" (where N is the number of elements)
  • exit
    • quit program