juston-li / virtual-memory Goto Github PK

Juston Li
950998500

Files:
translate.c
tlb.c
pagetable.c
io.c
binary.c
translate.h
addresses.txt
BACKING_STORE.bin
Makefile

Code layout
translate.c is the Main address translatation function
it opens/reads Address.txt file, initializes data structures
Then for each line in address.txt calls functions to convert to binary, 
lookup tlb, walk page table if tlb miss, then return the memory request

tlb.c handles tlb_lookup and tlb_update. tlb_lookup simply checks if the 
requests page is in the tlb array returning the corresponding page if it is. 
return -1 if it is not. tlb_update, updates the tlb given a page and its frame. 
It will take the first empty slot. If the tlb is full it uses LRU replacement, 
replacing the entry with the lowest counter. 
Note on a miss, pagetable.c will call tlb_update after the pagetable walk

pagetable.c on a tlb miss will check if the page requested is valid and in memory. 
If it is, it will update the TLB with the frame and return. An immediate TLB lookup
will follow it for a certain TLB hit
If the page is not in memory, load is called to bring the page to physicalmem_array, then
the pagetable, TLB are updated.

io.c handles I/O operations access and load. Access just returns the requested memory access
given the [frame][offset] in physicalmem_array. 
load opens the BACKING_STORE.bin and fseeks to the requested page. The page is read into the 
physicalmem_array into entry physicalmem_counter. So physicalmem_array is filled up sequentially,
by order of the memory requests. 

binary.c handles bin2dec and dec2bin functions.

BACKING_STORE.bin is just repeated lines of "0123456\n" to test correct access requests

Comments
Pretty fun project and didn't take much time.
I would actually have preferred an extended project on this than shells. 
Maybe include larger virtual than physical, mutiple TLB levels comparing different mapping techniques

Grace days: 3