Question

Question1

1. At the beginning of a procedure in Assembly, right after it is called, which of the following will work to put the value of the 7th argument into %rax?

   		movq (%rsp), %rax
   		movq 8(%rsp), %rax
   		leaq (%rsp), %rax
   		leaq 8(%rsp), %rax

Question2

Given the following code:

question2

Address: Instruction
400510: mov %rsp,%rdi

400513: callq 4004cd <sum>

400518: add $0x28,%rsp

When the callq instruction executes, what value will be pushed on to the Stack by call?

Question3

1. Given this following code:

   Address: Instruction

   4004ed: sub $0x20,%rsp
   4004f1: movq $0x1,(%rsp)
   4004f9: movq $0x2,0x8(%rsp)
   400502: movq $0x3,0x10(%rsp)
   40050a: movq $0x4,0x18(%rsp)

   Assume that %rsp is 0x1040 (the stack top is at address 0x1040).

   1) After executing the code on address 4004ed, what will the new value of %rsp be?  

   2) After executing the code on address 4004f1, what address will the value 1 go in to?

   3) After executing the code on address 40050a, what address will the value 4 go in to?

Answer 1

Question 1:

We can push the value of 7th argument  into %rax by making use of the option C.) movq 8(%rsp), %rax because of the fact the indicating 8 after the movq instruction and before the %rsp to indicating we are referring to the 7th argument and we need to move that argument into %rax , 8 before the %rsp means that we want to reder to the data at the rsp+8 , similarly we can access other values by indicating the value in multiple of 8 like 16 inidcates the rsp+16 and 32 indicates rsp+32.