根据提供的OS框架代码，补充完成logical memory部分的代码。
Requirement
In this assignment, you will implement a logical memory initializer for SOS.
The logical memory initializer will initialize the logical address space of a
process, and set up the page directory/tables for the process.
Background
The background material for this assignment is in Chapter 5 of “Understanding
a Simple Operating
System.” You must read it (and the previous chapters) before attempting this
assignment.
Assignment Objective
The file lmemman.c has one incomplete function with TODO blocks. Finish these
blocks to complete the assignment.
bool init_logical_memory(PCB *p, uint32_t code_size);
—|—
This function initializes a process’ logical address space. This involves
allocating frames for the process code, stacks, page directory and page
tables, and then setting them up. The PCB is passed in the argument p, and the
number of bytes in the process’ code and data is in the argument code_size.
The function should return TRUE if all goes well; otherwise FALSE. Any frames
allocated in the function must be freed if FALSE is returned.
User programs
The same user programs as in SOS2 are available in this assignment.
Setup
Download the ASG4.zip file from the assignment page. Extract the folder. In
SOS3, use ./create to create the SOS.dsk file (just like you did for SOS0,
SOS1 and SOS2). Create a new machine called SOS3 in VirtualBox, and use the
SOS.vmdk file for the hard drive. Once SOS boots, you can run one of the three
available programs. For example, to run p2.c, type
%run 1300 2
However, for now you will see the message run: Not enough memory. This is
because init_logical_memory simply returns FALSE. But once you finish the
assignment, you should see the program executing (you will see a series of Bs
being printed).
Submission
Submit in Canvas the modified lmemman.c file, and a README file containing any
information you feel the GTA should know before grading your program. Comment
your program well (include your name).
Grading
90 points total : 50 points are allocated for correct setup of the page
directory/tables, 10 points for allocating the correct number of frames, 20
points for correct setup of the process PCB’s mem struct, and 10 points for
correct return behavior. The assignment will be graded within the SOS
development environment. It is your responsibility to ensure that the
submitted code runs in that environment (irrespective of where you wrote or
tested your code). Failure to do so will result in full penalty.
The late policy is available in the course syllabus. You must work alone on
this assignment.
