user: 这段汇编代码用C语言表示是什么样的：

```asm
<qsort>:
  endbr64
  push   %r15
  mov    %edx,%r15d
  push   %r14
  mov    %rdi,%r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %esi,%ebx
  sub    $0x408,%rsp
  mov    %rcx,(%rsp)
  mov    %fs:0x28,%rax
  mov    %rax,0x3f8(%rsp)
  xor    %eax,%eax
  lea    0xd0(%rsp),%rax
  mov    %rax,0x28(%rsp)
  mov    %rax,%rbp
  cmp    $0x31f,%edx
  ja     L137
L52:
  mov    %r15d,%eax
  movl   $0x0,0x30(%rsp)
  movb   $0x0,0x0(%rbp,%rax,1)
  lea    -0x1(%rbx),%eax
  movl   $0x0,0x1c(%rsp)
  movl   $0x0,0x24(%rsp)
  mov    %eax,0x20(%rsp)
  mov    %eax,0x34(%rsp)
  mov    %r15d,%eax
  mov    %r14,%r15
  mov    %eax,%r14d
L27:
  subl   $0x1,0x24(%rsp)
  nopl   0x0(%rax)
L47:
  mov    0x1c(%rsp),%r12d
  mov    0x20(%rsp),%ebx
  mov    %r14d,%edx
  mov    %rbp,%rsi
  mov    %r12d,%eax
  add    %ebx,%eax
  mov    %eax,%edi
  shr    $0x1f,%edi
  add    %eax,%edi
  xor    %eax,%eax
  sar    %edi
  imul   %r14d,%edi
  add    %r15,%rdi
  call   <bmove@plt>
  mov    %r12d,%eax
  imul   %r14d,%eax
  mov    %eax,0x18(%rsp)
  lea    0x1(%r12),%eax
  mov    %eax,0x8(%rsp)
  nop
L135:
  mov    0x8(%rsp),%eax
  mov    0x18(%rsp),%r13d
  mov    %rbp,%rsi
  mov    (%rsp),%rdx
  sub    $0x1,%eax
  mov    %eax,0xc(%rsp)
  lea    (%r15,%r13,1),%rax
  mov    %rax,0x10(%rsp)
  mov    %rax,%rdi
  xor    %eax,%eax
  call   *%rdx
  test   %eax,%eax
  js     L93
  mov    %ebx,%r12d
  imul   %r14d,%r12d
  jmp    L63
  nopl   0x0(%rax,%rax,1)
L125:
  sub    $0x1,%ebx
L63:
  mov    %r12d,%r13d
  mov    (%rsp),%rcx
  mov    %rbp,%rdi
  xor    %eax,%eax
  add    %r15,%r13
  sub    %r14d,%r12d
  mov    %r13,%rsi
  call   *%rcx
  test   %eax,%eax
  js     L125
  cmp    0xc(%rsp),%ebx
  jge    L67
L21:
  mov    0x20(%rsp),%esi
  mov    0xc(%rsp),%edi
  mov    %ebx,%edx
  sub    0x1c(%rsp),%edx
  mov    %esi,%eax
  sub    %edi,%eax
  cmp    %eax,%edx
  jge    L62
  cmp    %edi,%esi
  jle    L148
  addl   $0x1,0x24(%rsp)
  movslq 0x24(%rsp),%rax
  mov    %ebx,0x20(%rsp)
  mov    %edi,0x30(%rsp,%rax,8)
  mov    %esi,0x34(%rsp,%rax,8)
L71:
  mov    0x20(%rsp),%edx
  cmp    %edx,0x1c(%rsp)
  jl     L47
  movslq 0x24(%rsp),%rax
  cmp    $0xffffffff,%eax
  je     L46
  mov    0x30(%rsp,%rax,8),%edx
  mov    0x34(%rsp,%rax,8),%eax
  mov    %edx,0x1c(%rsp)
  mov    %eax,0x20(%rsp)
  jmp    L27
  nopl   (%rax)
L67:
  mov    0x10(%rsp),%rsi
  mov    %r13,%rdx
  mov    %r14d,%edi
  xor    %eax,%eax
  sub    $0x1,%ebx
  call   <_swap@plt>
  mov    0x8(%rsp),%eax
  mov    %eax,0xc(%rsp)
  cmp    %ebx,%eax
  jg     L21
L93:
  add    %r14d,0x18(%rsp)
  addl   $0x1,0x8(%rsp)
  jmp    L135
L62:
  mov    0x1c(%rsp),%edx
  cmp    %ebx,%edx
  jge    L25
  addl   $0x1,0x24(%rsp)
  movslq 0x24(%rsp),%rax
  mov    %edx,0x30(%rsp,%rax,8)
  mov    %ebx,0x34(%rsp,%rax,8)
  mov    0xc(%rsp),%eax
  mov    %eax,0x1c(%rsp)
  jmp    L71
L148:
  mov    %ebx,0x20(%rsp)
  jmp    L71
L25:
  mov    0xc(%rsp),%eax
  mov    %eax,0x1c(%rsp)
  jmp    L71
L46:
  cmp    0x28(%rsp),%rbp
  je     L123
  mov    %rbp,%rdi
  call   <free@plt>
L123:
  mov    0x3f8(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L136
  add    $0x408,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L137:
  lea    0x1(%rdx),%edi
  xor    %eax,%eax
  call   <malloc@plt>
  mov    %rax,%rbp
  test   %rax,%rax
  jne    L52
  jmp    L123
L136:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
qsort(base, nel, width, compar) char *base;
int (*compar)();
unsigned width, nel;
{
  register char *x;
  extern char *malloc();
  register int i, j, l, r;
  struct {
    int l, r;
  } stack[20];
  int s;
  char xbuf[800];
  if (width < sizeof xbuf)
    x = xbuf;
  else if (!(x = malloc(width + 1)))
    return;
  x[width] = 0;
  s = 0;
  stack[0].l = 0;
  stack[0].r = nel - 1;
  do {
    l = stack[s].l;
    r = stack[s--].r;
    do {
      i = l;
      j = r;
      bmove(base + width * ((i + j) / 2), x, width);
      do {
        while ((*compar)(base + i * width, x) < 0)
          i++;
        while ((*compar)(x, base + j * width) < 0)
          j--;
        if (i <= j) {
          _swap(width, base + i * width, base + j * width);
          i++;
          j--;
        }
      } while (i <= j);
      if (j - l < r - i) {
        if (i < r) {
          stack[++s].l = i;
          stack[s].r = r;
        }
        r = j;
      } else {
        if (l < j) {
          stack[++s].l = l;
          stack[s].r = j;
        }
        l = i;
      }
    } while (l < r);
  } while (s >= 0);
  if (x != xbuf)
    free(x);
}
```