c program:
#include <stdio.h>
int add(int a, int b)
{
  int output;
  output = a+b;
  return output;
}

int main()
{
 int answer;
 answer = add(3,5);
 return 0;
}

assembly output:
Dump of assembler code for function main:
10  {
0x0000000000400507 <+0>:    push   %rbp
0x0000000000400508 <+1>:    mov    %rsp,%rbp
0x000000000040050b <+4>:    sub    $0x10,%rsp

11      int answer;
12      answer = add(3,5);
0x000000000040050f <+8>:    mov    $0x5,%esi
0x0000000000400514 <+13>:   mov    $0x3,%edi
0x0000000000400519 <+18>:   callq  0x4004ed <add>
0x000000000040051e <+23>:   mov    %eax,-0x4(%rbp)

13    return 0;
0x0000000000400521 <+26>:   mov    $0x0,%eax

14  }
0x0000000000400526 <+31>:   leaveq
0x0000000000400527 <+32>:   retq

End of assembler dump.

0x000000000040050b 10  {
 7: $rip = (void (*)()) 0x40050b <main+4>
 6: $rdx = 140737488346616
 5: $rax = 4195591
 4: $rdi = 1
 3: $rsi = 140737488346600
 2: $rsp = (void *) 0x7fffffffdd00
 1: $rbp = (void *) 0x7fffffffdd00
(gdb) x /8wx $rsp
0x7fffffffdd00: 0x00000000  0x00000000  0xf7a36f45  0x00007fff
0x7fffffffdd10: 0x00000000  0x00000000  0xffffdde8  0x00007fff
(gdb) stepi
 12     answer = add(3,5);
 7: $rip = (void (*)()) 0x40050f <main+8>
 6: $rdx = 140737488346616 ------> hex value 0x7FFFFFFFDDF8
 5: $rax = 4195591 ---------------> hex value 0x400507
 4: $rdi = 1
 3: $rsi = 140737488346600---------> hex value  0x7FFFFFFFDDE8
 2: $rsp = (void *) 0x7fffffffdcf0
 1: $rbp = (void *) 0x7fffffffdd00
 (gdb) x /8wx $rsp
 0x7fffffffdcf0:    0xffffdde0  0x00007fff  0x00000000  0x00000000
 0x7fffffffdd00:    0x00000000  0x00000000  0xf7a36f45  0x00007fff