user: 下面的汇编指令对应的C源代码是什么：

```asm
<qsort>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x38,%rsp
  mov    %rdi,-0x48(%rbp)
  mov    %rsi,-0x50(%rbp)
  mov    %rdx,%r15
  mov    %rcx,%r13
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  cmp    $0x3,%rsi
  ja     L10
  cmp    $0x2,%rsi
  je     L1
  cmpq   $0x3,-0x50(%rbp)
  jne    L97
  mov    -0x48(%rbp),%rsi
  lea    (%rsi,%rdx,1),%rbx
  mov    %rbx,%rdi
  call   *%rcx
  test   %eax,%eax
  js     L14
L76:
  mov    -0x48(%rbp),%rax
  lea    (%rax,%r15,2),%r12
  mov    %rbx,%rsi
  mov    %r12,%rdi
  call   *%r13
  test   %eax,%eax
  jns    L97
  mov    %r15,%rdx
  mov    %r12,%rsi
  mov    %rbx,%rdi
  call   <swap@plt>
  mov    -0x48(%rbp),%rsi
  mov    %rbx,%rdi
  call   *%r13
  test   %eax,%eax
  jns    L97
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    -0x48(%rbp),%rdi
  call   <swap@plt>
  jmp    L97
L1:
  mov    %rdi,%rsi
  lea    (%rdi,%rdx,1),%rbx
  mov    %rbx,%rdi
  call   *%rcx
  test   %eax,%eax
  jns    L97
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    -0x48(%rbp),%rdi
  call   <swap@plt>
  jmp    L97
L14:
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    -0x48(%rbp),%rdi
  call   <swap@plt>
  jmp    L76
L10:
  mov    $0x0,%eax
  call   <rand@plt>
  lea    0x17(%r15),%rdx
  mov    %rdx,%rsi
  and    $0xfffffffffffffff0,%rsi
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L44:
  cmp    %rcx,%rsp
  je     L172
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L44
L172:
  mov    %rsi,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L232
  orq    $0x0,-0x8(%rsp,%rdx,1)
L232:
  lea    0xf(%rsp),%r14
  and    $0xfffffffffffffff0,%r14
  mov    -0x50(%rbp),%rdi
  lea    -0x1(%rdi),%rdx
  imul   %r15,%rdx
  mov    -0x48(%rbp),%r12
  add    %r12,%rdx
  mov    %rdx,%rbx
  mov    %rdx,-0x58(%rbp)
  mov    $0x0,%edx
  div    %rdi
  imul   %r15,%rdx
  lea    (%r12,%rdx,1),%rsi
  mov    %r15,%rdx
  mov    %r14,%rdi
  call   <memcpy@plt>
  jmp    L21
L92:
  add    %r15,%r12
L176:
  mov    %r14,%rsi
  mov    %r12,%rdi
  call   *%r13
  test   %eax,%eax
  js     L92
  jmp    L40
L94:
  sub    %r15,%rbx
L40:
  mov    %rbx,%rsi
  mov    %r14,%rdi
  call   *%r13
  test   %eax,%eax
  js     L94
  cmp    %rbx,%r12
  jbe    L188
L21:
  cmp    %rbx,%r12
  jbe    L176
  cmp    -0x48(%rbp),%rbx
  ja     L42
L170:
  cmp    -0x58(%rbp),%r12
  jb     L237
L97:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L127
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L188:
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    %r12,%rdi
  call   <swap@plt>
  add    %r15,%r12
  sub    %r15,%rbx
  jmp    L21
L42:
  mov    %rbx,%rax
  mov    -0x48(%rbp),%rdi
  sub    %rdi,%rax
  mov    $0x0,%edx
  div    %r15
  lea    0x1(%rax),%rsi
  mov    %r13,%rcx
  mov    %r15,%rdx
  call   <qsort>
  jmp    L170
L237:
  mov    %r12,%rax
  sub    -0x48(%rbp),%rax
  mov    $0x0,%edx
  div    %r15
  mov    -0x50(%rbp),%rsi
  sub    %rax,%rsi
  mov    %r13,%rcx
  mov    %r15,%rdx
  mov    %r12,%rdi
  call   <qsort>
  jmp    L97
L127:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void qsort(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *)) {
  if (nmemb < 4) {
    if (nmemb == 2) {
      if (compar(base + size, base) < 0) {
        swap(base, base + size, size);
      }
    } else if (nmemb == 3) {
      if (compar(base + size, base) < 0) {
        swap(base, base + size, size);
      }
      if (compar(base + (size << 1), base + size) < 0) {
        swap(base + size, base + (size << 1), size);
        if (compar(base + size, base) < 0) {
          swap(base, base + size, size);
        }
      }
    }
    return;
  } else {
    void *pos = (rand() % nmemb) * size + base;
    void *key = alloca(size);
    void *i = base, *j = base + (size * (nmemb - 1));
    memcpy(key, pos, size);
    while (i <= j) {
      while (compar(i, key) < 0) {
        i += size;
      }
      while (compar(key, j) < 0) {
        j -= size;
      }
      if (i <= j) {
        swap(i, j, size);
        i += size;
        j -= size;
      }
    }
    if (j > base) {
      qsort(base, (j - base) / size + 1, size, compar);
    }
    if (i < base + (nmemb - 1) * size) {
      qsort(i, nmemb - (i - base) / size, size, compar);
    }
  }
}
```