user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<quicksort>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %edx,0x24(%rsp)
  cmp    %esi,%edx
  jle    L9
  mov    %rdi,%r15
  mov    %esi,%r13d
L179:
  mov    0x24(%rsp),%edx
  mov    %r13d,%esi
  mov    %r15,%rdi
  call   <partition@plt>
  mov    %eax,0x28(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x18(%rsp)
  cmp    %r13d,%eax
  jle    L157
  mov    %r13d,%r14d
  mov    %r15,%r13
L15:
  mov    0x18(%rsp),%edx
  mov    %r14d,%esi
  mov    %r13,%rdi
  call   <partition@plt>
  mov    %eax,0x2c(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x1c(%rsp)
  cmp    %r14d,%eax
  jle    L37
  mov    %r14d,%eax
  mov    %r13,%r14
  mov    %eax,%r13d
L143:
  mov    0x1c(%rsp),%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  call   <partition@plt>
  mov    %eax,0x30(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x20(%rsp)
  cmp    %r13d,%eax
  jle    L106
L45:
  mov    0x20(%rsp),%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  call   <partition@plt>
  lea    -0x1(%rax),%r12d
  mov    %eax,0x34(%rsp)
  cmp    %r13d,%r12d
  jle    L84
L177:
  mov    %r12d,%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  call   <partition@plt>
  lea    -0x1(%rax),%ebx
  mov    %eax,%ebp
  cmp    %r13d,%ebx
  jle    L140
  mov    %r12d,0x8(%rsp)
  mov    %r13d,%r15d
  mov    %ebx,%ebp
  mov    %r14,%r13
  mov    %eax,%r14d
L105:
  mov    %ebp,%edx
  mov    %r15d,%esi
  mov    %r13,%rdi
  call   <partition@plt>
  lea    -0x1(%rax),%ebx
  mov    %eax,0x10(%rsp)
  cmp    %r15d,%ebx
  jle    L85
  mov    %ebp,0xc(%rsp)
  mov    %ebx,%ebp
  mov    %r13,%rbx
L57:
  mov    %ebp,%edx
  mov    %r15d,%esi
  mov    %rbx,%rdi
  call   <partition@plt>
  lea    -0x1(%rax),%r13d
  mov    %eax,0x38(%rsp)
  cmp    %r15d,%r13d
  jle    L14
  mov    %ebp,0x14(%rsp)
  mov    %rbx,%rbp
  mov    %r13d,%ebx
L110:
  mov    %ebx,%edx
  mov    %r15d,%esi
  mov    %rbp,%rdi
  call   <partition@plt>
  lea    -0x1(%rax),%r13d
  mov    %eax,%r12d
  cmp    %r15d,%r13d
  jle    L5
  mov    %ebx,%r12d
  mov    %eax,%ecx
  mov    %r13d,%ebx
L21:
  mov    %r15d,%esi
  mov    %ebx,%edx
  mov    %rbp,%rdi
  mov    %ecx,0x3c(%rsp)
  call   <partition@plt>
  mov    %r15d,%esi
  mov    %rbp,%rdi
  mov    %eax,%r13d
  lea    -0x1(%rax),%edx
  call   <quicksort>
  lea    0x1(%r13),%r15d
  mov    0x3c(%rsp),%ecx
  cmp    %r15d,%ebx
  jg     L21
  mov    %r12d,%ebx
  mov    %ecx,%r12d
L5:
  lea    0x1(%r12),%r15d
  cmp    %r15d,%ebx
  jg     L110
  mov    %rbp,%rbx
  mov    0x14(%rsp),%ebp
L14:
  mov    0x38(%rsp),%r15d
  add    $0x1,%r15d
  cmp    %r15d,%ebp
  jg     L57
  mov    0xc(%rsp),%ebp
  mov    %rbx,%r13
L85:
  mov    0x10(%rsp),%r15d
  add    $0x1,%r15d
  cmp    %r15d,%ebp
  jg     L105
  mov    0x8(%rsp),%r12d
  mov    %r14d,%ebp
  mov    %r13,%r14
L140:
  lea    0x1(%rbp),%r13d
  cmp    %r13d,%r12d
  jg     L177
L84:
  mov    0x34(%rsp),%r13d
  add    $0x1,%r13d
  cmp    %r13d,0x20(%rsp)
  jg     L45
L106:
  mov    0x30(%rsp),%r13d
  add    $0x1,%r13d
  cmp    %r13d,0x1c(%rsp)
  jg     L143
  mov    %r14,%r13
L37:
  mov    0x2c(%rsp),%r14d
  add    $0x1,%r14d
  cmp    %r14d,0x18(%rsp)
  jg     L15
  mov    %r13,%r15
L157:
  mov    0x28(%rsp),%r13d
  add    $0x1,%r13d
  cmp    0x24(%rsp),%r13d
  jl     L179
L9:
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void quicksort(int a[], int l, int u) {
  int j;
  if (l < u) {
    j = partition(a, l, u);
    quicksort(a, l, j - 1);
    quicksort(a, j + 1, u);
  }
}
```