user: 请从给定的汇编指令推导出C源代码：

```asm
<parse_prereq>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %rdi,-0x38(%rbp)
  mov    %rsi,-0x40(%rbp)
  mov    -0x38(%rbp),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x38(%rbp),%rax
  add    $0x4,%rax
  mov    %rax,-0x30(%rbp)
  jmp    L4
L30:
  mov    -0x30(%rbp),%rax
  mov    (%rax),%ebx
  mov    $0x434f4e46,%edi
  call   <ntohl@plt>
  cmp    %eax,%ebx
  jne    L44
  mov    -0x30(%rbp),%rax
  mov    %rax,-0x28(%rbp)
  jmp    L86
L44:
  mov    -0x30(%rbp),%rax
  mov    (%rax),%ebx
  mov    $0x4f4e4649,%edi
  call   <ntohl@plt>
  cmp    %eax,%ebx
  jne    L60
  mov    -0x30(%rbp),%rax
  sub    $0x1,%rax
  mov    %rax,-0x28(%rbp)
  jmp    L86
L60:
  mov    -0x30(%rbp),%rax
  mov    (%rax),%ebx
  mov    $0x4e464947,%edi
  call   <ntohl@plt>
  cmp    %eax,%ebx
  jne    L82
  mov    -0x30(%rbp),%rax
  sub    $0x2,%rax
  mov    %rax,-0x28(%rbp)
  jmp    L86
L82:
  mov    -0x30(%rbp),%rax
  mov    (%rax),%ebx
  mov    $0x4649475f,%edi
  call   <ntohl@plt>
  cmp    %eax,%ebx
  jne    L40
  mov    -0x30(%rbp),%rax
  sub    $0x3,%rax
  mov    %rax,-0x28(%rbp)
L86:
  mov    -0x40(%rbp),%rax
  lea    -0x7(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  cmp    %rax,-0x28(%rbp)
  ja     L65
  mov    -0x28(%rbp),%rax
  mov    $0x7,%edx
  lea    D6(%rip),%rcx
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <memcmp@plt>
  test   %rax,%rax
  jne    L207
  mov    -0x28(%rbp),%rax
  add    $0x7,%rax
  mov    %rax,-0x20(%rbp)
  jmp    L25
L105:
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isalnum@plt>
  test   %rax,%rax
  jne    L119
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x5f,%al
  je     L119
  mov    -0x20(%rbp),%rax
  sub    -0x28(%rbp),%rax
  cmp    $0x6,%rax
  jle    L133
  mov    -0x20(%rbp),%rax
  sub    -0x28(%rbp),%rax
  sub    $0x7,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    $0x7,%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <update_prereq@plt>
  jmp    L133
L119:
  addq   $0x1,-0x20(%rbp)
L25:
  mov    -0x38(%rbp),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  cmp    %rax,-0x20(%rbp)
  jb     L105
  jmp    L51
L40:
  nop
  jmp    L51
L65:
  nop
  jmp    L51
L207:
  nop
  jmp    L51
L133:
  nop
L51:
  addq   $0x4,-0x30(%rbp)
L4:
  mov    -0x30(%rbp),%rax
  cmp    -0x18(%rbp),%rax
  jb     L30
  nop
  nop
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

tool_calls: name: parse_data
arguments: tag: D6
datatype: string

tool: D6: CONFIG_

assistant: ```c
void parse_prereq(const char *map, size_t len) {
  const int *end = (const int *)(map + len);
  const int *m = (const int *)map + 1;
  const char *p, *q;
  for (; m < end; m++) {
    if (*m == ntohl(0x434f4e46))
      p = (char *)m;
    else if (*m == ntohl(0x4f4e4649))
      p = (char *)m - 1;
    else if (*m == ntohl(0x4e464947))
      p = (char *)m - 2;
    else if (*m == ntohl(0x4649475f))
      p = (char *)m - 3;
    else
      continue;
    if (p > map + len - 7)
      continue;
    if (memcmp(p, "CONFIG_", 7))
      continue;
    for (q = p + 7; q < map + len; q++) {
      if (!(isalnum(*q) || *q == '_')) {
        if ((q - p - 7) >= 0)
          update_prereq(p + 7, q - p - 7);
        break;
      }
    }
  }
}
```