Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Each function has its own stack frame between %fp and %sp. Let Caller calls Callee. Then Caller's %sp becomes callee's %fp, and callee's %sp set to be a new value (a smaller one because stack grows from large address to small address). You can think that Callee's stack frame is on top of Caller's stack frame.
In Caller: put arguments in %o0 to %o5 registers or if number of arguments more than 6, prepare values in call linkage of the current stack frame. Then "call" address_of_callee; %o7 stored the returned address. (This %o7 will becomes %i7 in callee after the callee executes save instruction.)
In Callee: it executes "save" instruction:
So at this point in callee, %i6 (%fp was caller's %o6) is set, and %o6 (%sp is set to be a new value). Question: where is the old %fp? It is stored somewhere in the top portion of the previous stack frame (see step 0.) The return address of Callee is stored in %i7. Is it possible to write a program to overflow this %i7? What return address that you really can overflow? Question: how to access that return address.
The "restore" instruction is the inverse function of save. Then the "ret" instruction should branch to %i7+8. The normal address should be %i7+4 as the next instruction address after call. The extra 4 is because sparc has a "branch delay" instruction that is executed BEFORE the call is made even it is put just after CALL. Is it strange. Not really. This is because modern CPU is a pipeline machine. It loads instruction every clock cycle, and branch (or jump or call) somewhat cannot be really done until the later stage the pipeline. And then it is already too late because the one JUST after this branch has already been executed. If you want to know more, you should take a look at computer architecture textbook which I think every graduate should know.
You should be very clear what return address in server.c is overflowed? Is it the return address of main() or the return address of copy()?
program to write superposition of waves using class and objects
what is c++ language?
Q: How can one encourage his (older) compiler to check new to see automatically if it returns NULL? A: His compiler eventually will. If he contain an old compiler wh
Within software languages we have the ability to store information in mail boxes i.e. memory slots which are given names to represent the box. The naming rules are governed by the
How would you print the values of the variables words and lines so they appear in the form: There were 6040 words and 680 lines. Here, 6040 and 680 represent the values of the two
write a class player that contains attributes for player name,avg and team.write three functions to input,change and display these attributes.also write a constructor that asks for
Operation on array: void Array::add( Object& toAdd ) { lastElementIndex++; while( ptrAt( lastElementIndex ) != ZERO && lastElementIndex
Requirements Create a "makefile" that will manage the construction of a program The name of the makefile must be: makefile The make file must produce an executable
Aim: To implement a program to swap two numbers using reference arguments. Code: void swap(int *a, int *b) { int temp; temp=*a;
Use the program called harris-shell.c and add some code to find the corners in the image checkers.jpg. You should say that a pixel in the image is a corner if it passes the given t
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd