user: Please show me the C implementation that matches the assembly code listed below:

```asm
<ft_atoi>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x0,-0x1c(%rbp)
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L103
  mov    $0x0,%eax
  jmp    L94
L36:
  mov    -0x1c(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,-0x1c(%rbp)
L103:
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jle    L104
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x20,%al
  jg     L104
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2d,%al
  jne    L36
L104:
  movq   $0x1,-0x10(%rbp)
  mov    -0x1c(%rbp),%eax
  mov    %eax,-0x18(%rbp)
  jmp    L77
L17:
  mov    -0x10(%rbp),%rdx
  mov    %rdx,%rax
  shl    $0x2,%rax
  add    %rdx,%rax
  add    %rax,%rax
  mov    %rax,-0x10(%rbp)
L77:
  addl   $0x1,-0x18(%rbp)
  mov    -0x18(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jle    L34
  mov    -0x18(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jle    L17
L34:
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%ecx
  lea    -0x1c(%rbp),%rdx
  lea    -0x10(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <is_negative@plt>
  movl   $0x0,-0x14(%rbp)
  jmp    L54
L6:
  mov    -0x1c(%rbp),%eax
  lea    0x1(%rax),%edx
  mov    %edx,-0x1c(%rbp)
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  sub    $0x30,%eax
  movslq %eax,%rdx
  mov    -0x10(%rbp),%rax
  imul   %rdx,%rax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x10(%rbp),%rcx
  movabs $0x6666666666666667,%rdx
  mov    %rcx,%rax
  imul   %rdx
  mov    %rdx,%rax
  sar    $0x2,%rax
  sar    $0x3f,%rcx
  mov    %rcx,%rdx
  sub    %rdx,%rax
  mov    %rax,-0x10(%rbp)
L54:
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jle    L51
  mov    -0x1c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jle    L6
L51:
  mov    -0x14(%rbp),%eax
L94:
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L72
  call   <__stack_chk_fail@plt>
L72:
  leave
  ret
```

assistant: ```c
int ft_atoi(char *str) {
  int num_start;
  int mult_it;
  long int mult;
  int resault;
  num_start = 0;
  if (str[num_start] == 0)
    return (0);
  while (str[num_start] > 0 && str[num_start] <= 32 && str[num_start] != '-')
    num_start++;
  mult = 1;
  mult_it = num_start;
  while (str[++mult_it] >= '0' && str[mult_it] <= '9')
    mult *= 10;
  is_negative(&mult, str[num_start], &num_start);
  resault = 0;
  while (str[num_start] >= '0' && str[num_start] <= '9') {
    resault += (str[num_start++] - 48) * mult;
    mult /= 10;
  }
  return (resault);
}
```