user: 下面的汇编指令对应的C源代码是什么：

```asm
<quicksort>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  mov    %rsi,%r13
  lea    -0x1(%rdx),%esi
  push   %r12
  push   %rbp
  push   %rbx
  movslq %ecx,%rbx
  imul   %r13,%rbx
  sub    $0x48,%rsp
  mov    %esi,0x28(%rsp)
  lea    -0x1(%rcx),%esi
  add    %rdi,%rbx
  mov    %esi,0x30(%rsp)
  lea    0x1(%rcx),%esi
  mov    %rdi,0x18(%rsp)
  mov    %edx,0x8(%rsp)
  mov    %ecx,0x24(%rsp)
  mov    %esi,0x34(%rsp)
  cmp    %edx,%ecx
  jle    L93
  mov    %rbx,0x38(%rsp)
  mov    %r8,%r14
L24:
  xor    %eax,%eax
  call   <rand@plt>
  mov    0x24(%rsp),%ebx
  mov    0x8(%rsp),%esi
  cltd
  mov    0x18(%rsp),%rbp
  mov    %ebx,%ecx
  sub    %esi,%ecx
  mov    %rbp,%rdi
  idiv   %ecx
  mov    %ebx,%ecx
  add    %esi,%edx
  mov    %r13,%rsi
  call   <exch@plt>
  mov    0x28(%rsp),%eax
  mov    %ebx,0x2c(%rsp)
  lea    0x1(%rax),%r15d
  mov    %eax,0x20(%rsp)
  movslq %r15d,%r15
  imul   %r13,%r15
  add    %rbp,%r15
  mov    %r15,0x10(%rsp)
  mov    %ebx,%r15d
  mov    0x38(%rsp),%rbx
  nopw   0x0(%rax,%rax,1)
L198:
  add    $0x1,%eax
  mov    %eax,0xc(%rsp)
  cmp    %eax,0x24(%rsp)
  je     L95
  mov    0x10(%rsp),%rdi
  mov    %rbx,%rsi
  call   *%r14
  test   %eax,%eax
  js     L36
L95:
  movslq %r15d,%rdx
  mov    0x18(%rsp),%rax
  mov    %r15d,%ebp
  sub    $0x1,%rdx
  imul   %r13,%rdx
  lea    (%rax,%rdx,1),%r12
  jmp    L32
  nopl   (%rax)
L19:
  test   %eax,%eax
  jns    L187
L32:
  mov    %r12,%rsi
  mov    %r12,%r15
  mov    %rbx,%rdi
  sub    $0x1,%ebp
  call   *%r14
  sub    %r13,%r12
  cmp    0x8(%rsp),%ebp
  jne    L19
L187:
  mov    0xc(%rsp),%edx
  mov    %ebp,%eax
  mov    %r15,%rbp
  mov    %eax,%r15d
  cmp    %eax,%edx
  jge    L12
  mov    0x18(%rsp),%rdi
  mov    %r13,%rsi
  mov    %eax,%ecx
  call   <exch@plt>
  mov    0x10(%rsp),%rdi
  mov    %rbx,%rsi
  call   *%r14
  test   %eax,%eax
  je     L196
L0:
  mov    %rbp,%rsi
  mov    %rbx,%rdi
  call   *%r14
  test   %eax,%eax
  je     L145
L36:
  mov    0xc(%rsp),%eax
  add    %r13,0x10(%rsp)
  mov    %eax,0x20(%rsp)
  jmp    L198
  nopl   (%rax)
L145:
  subl   $0x1,0x2c(%rsp)
  mov    0x18(%rsp),%rdi
  mov    %r15d,%edx
  mov    %r13,%rsi
  mov    0x2c(%rsp),%ecx
  call   <exch@plt>
  jmp    L36
  nopl   0x0(%rax,%rax,1)
L196:
  addl   $0x1,0x28(%rsp)
  mov    0x28(%rsp),%eax
  mov    %r13,%rsi
  mov    0xc(%rsp),%ecx
  mov    0x18(%rsp),%rdi
  mov    %eax,%edx
  call   <exch@plt>
  jmp    L0
  xchg   %ax,%ax
L12:
  mov    0x24(%rsp),%ecx
  mov    0x18(%rsp),%rdi
  mov    %r13,%rsi
  call   <exch@plt>
  mov    0x20(%rsp),%esi
  mov    0x28(%rsp),%r12d
  lea    0x2(%rsi),%eax
  mov    %eax,0x10(%rsp)
  mov    0x8(%rsp),%eax
  cmp    %eax,%r12d
  jle    L9
  lea    (%rax,%rsi,1),%ebp
  mov    %eax,%ebx
  mov    %ebp,%r15d
  mov    0x18(%rsp),%rbp
  nopl   0x0(%rax,%rax,1)
L97:
  mov    %r15d,%ecx
  mov    %ebx,%edx
  mov    %r13,%rsi
  mov    %rbp,%rdi
  sub    %ebx,%ecx
  add    $0x1,%ebx
  call   <exch@plt>
  cmp    %ebx,%r12d
  jne    L97
  mov    0x20(%rsp),%edi
  mov    0x2c(%rsp),%ebx
  mov    0x30(%rsp),%r15d
  mov    0x8(%rsp),%eax
  sub    0x28(%rsp),%eax
  lea    (%rax,%rdi,1),%r12d
  cmp    %r15d,%ebx
  jge    L135
L147:
  mov    0x20(%rsp),%ebp
  add    0x34(%rsp),%ebp
  mov    %r12d,0xc(%rsp)
  mov    %r15d,%r12d
  mov    %ebp,%r15d
  mov    0x18(%rsp),%rbp
  nopl   0x0(%rax)
L7:
  mov    %r15d,%edx
  mov    %r12d,%ecx
  mov    %r13,%rsi
  mov    %rbp,%rdi
  sub    %r12d,%edx
  sub    $0x1,%r12d
  call   <exch@plt>
  cmp    %r12d,%ebx
  jne    L7
  mov    0x10(%rsp),%eax
  mov    0x30(%rsp),%edi
  mov    0xc(%rsp),%r12d
  lea    (%rdi,%rax,1),%edx
  mov    0x2c(%rsp),%edi
  sub    %edi,%edx
  sub    %edi,%eax
  mov    0x24(%rsp),%edi
  mov    %edx,0x10(%rsp)
  lea    -0x2(%rax,%rdi,1),%eax
  mov    %eax,0x28(%rsp)
L186:
  mov    0x8(%rsp),%edx
  mov    0x18(%rsp),%rdi
  mov    %r14,%r8
  mov    %r12d,%ecx
  mov    %r13,%rsi
  call   <quicksort>
  mov    0x10(%rsp),%eax
  cmp    %eax,0x24(%rsp)
  jle    L93
  mov    %eax,0x8(%rsp)
  jmp    L24
L93:
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L9:
  mov    0x2c(%rsp),%ebx
  mov    0x30(%rsp),%r15d
  mov    %esi,%r12d
  cmp    %r15d,%ebx
  jl     L147
L135:
  mov    0xc(%rsp),%eax
  mov    %eax,0x28(%rsp)
  jmp    L186
```

assistant: ```c
void quicksort(char *base, size_t size, ssize_t l, ssize_t r, int (*compar)(const void *, const void *)) {
  ssize_t i = l - 1, j = r, p = l - 1, q = r, k;
  char *v = base + r * size;
  if (r <= l)
    return;
  exch(base, size, l + (rand() % (r - l)), r);
  for (;;) {
    while (++i != r && compar(base + i * size, v) < 0)
      ;
    while (compar(v, base + (--j) * size) < 0)
      if (j == l)
        break;
    if (i >= j)
      break;
    exch(base, size, i, j);
    if (compar(base + i * size, v) == 0)
      exch(base, size, ++p, i);
    if (compar(v, base + j * size) == 0)
      exch(base, size, j, --q);
  }
  exch(base, size, i, r);
  j = i - 1;
  ++i;
  for (k = l; k < p; k++, j--)
    exch(base, size, k, j);
  for (k = r - 1; k > q; k--, i++)
    exch(base, size, i, k);
  quicksort(base, size, l, j, compar);
  quicksort(base, size, i, r, compar);
}
```