Some questions bout assemblycode build with gcc

[Stephan Kallnik]

I have build this following c programm with the two different gcc
compilers:

#include  <stdio.h>
#include  <string.h>

void func (char *str_ptr) {
  char stack_temp[4];
  // strcpy(stack_temp,str_ptr);
}

int main ( ) {
  func("TEST");
  return 0;
}


No i have some question to two different assembler instruction, which
the gcc build:

gcc 2.91:

0x80483d0 <main>:       push   %ebp
0x80483d1 <main+1>:     mov    %esp,%ebp
0x80483d3 <main+3>:     push   $0x8048464
0x80483d8 <main+8>:     call   0x80483c0 <func>
0x80483dd <main+13>:    add    $0x4,%esp
0x80483e0 <main+16>:    xor    %eax,%eax
0x80483e2 <main+18>:    jmp    0x80483f0 <main+32>
0x80483e4 <main+20>:    lea    0x0(%esi),%esi
0x80483ea <main+26>:    lea    0x0(%edi),%edi
0x80483f0 <main+32>:    mov    %ebp,%esp
0x80483f2 <main+34>:    pop    %ebp
0x80483f3 <main+35>:    ret        

First question is: What does the lines main+18 til main+26 do?

gcc 2.95:

this compiler generates two extra lines like between main+1 and main+3:
                        sub     $0x8,%esp
                        add     $0xfffffff4,%esp
What will this lines do or for what they reserve the space in the stack?
This extralines are similar in the function func. But when you debug the
stack while you write a string in stack_temp, you see that they are
placed at the same position as in the build with gcc 2.91



  I know this are perhaps simple questions but i don't know.
  But thank for some answer