user: Please show me the C implementation that matches the assembly code listed below:

```asm
<qsort>:
  endbr64
  push   %r15
  mov    %rdi,%r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %esi,0x34(%rsp)
  mov    %edx,0x38(%rsp)
L149:
  mov    0x34(%rsp),%ebx
  mov    0x38(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  mov    %ebx,0x2c(%rsp)
  call   <part@plt>
  mov    %eax,0x34(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x30(%rsp)
  cmp    %ebx,%eax
  jg     L80
L127:
  mov    0x34(%rsp),%ecx
  cmp    %ecx,0x38(%rsp)
  jg     L149
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L80:
  mov    0x2c(%rsp),%ebx
  mov    0x30(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  mov    %ebx,0x20(%rsp)
  call   <part@plt>
  mov    %eax,0x2c(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x28(%rsp)
  cmp    %eax,%ebx
  jl     L26
L77:
  mov    0x2c(%rsp),%ecx
  cmp    %ecx,0x30(%rsp)
  jg     L80
  jmp    L127
  nopl   0x0(%rax)
L26:
  mov    0x20(%rsp),%ebx
  mov    0x28(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  mov    %ebx,0x18(%rsp)
  call   <part@plt>
  mov    %eax,0x20(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x1c(%rsp)
  cmp    %eax,%ebx
  jl     L261
L133:
  mov    0x20(%rsp),%ecx
  cmp    %ecx,0x28(%rsp)
  jg     L26
  jmp    L77
  nopl   0x0(%rax)
L261:
  mov    0x18(%rsp),%ebx
  mov    0x1c(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  mov    %ebx,0x10(%rsp)
  call   <part@plt>
  mov    %eax,0x18(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x14(%rsp)
  cmp    %eax,%ebx
  jl     L97
L238:
  mov    0x18(%rsp),%ecx
  cmp    %ecx,0x1c(%rsp)
  jg     L261
  jmp    L133
  nopl   0x0(%rax)
L97:
  mov    0x10(%rsp),%ebx
  mov    0x14(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  mov    %ebx,0x8(%rsp)
  call   <part@plt>
  mov    %eax,0x10(%rsp)
  sub    $0x1,%eax
  mov    %eax,0xc(%rsp)
  cmp    %eax,%ebx
  jl     L109
L44:
  mov    0x10(%rsp),%ecx
  cmp    %ecx,0x14(%rsp)
  jg     L97
  jmp    L238
  nopl   0x0(%rax)
L109:
  mov    0x8(%rsp),%ebx
  mov    0xc(%rsp),%edx
  mov    %r15,%rdi
  mov    %ebx,%esi
  call   <part@plt>
  mov    %eax,0x8(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x4(%rsp)
  cmp    %eax,%ebx
  jl     L9
L157:
  mov    0x8(%rsp),%ecx
  cmp    %ecx,0xc(%rsp)
  jg     L109
  jmp    L44
  nopl   (%rax)
L9:
  mov    0x4(%rsp),%edx
  mov    %ebx,%esi
  mov    %r15,%rdi
  mov    %ebx,%r14d
  call   <part@plt>
  lea    -0x1(%rax),%r12d
  mov    %eax,%ebx
  cmp    %r12d,%r14d
  jl     L121
L244:
  cmp    %ebx,0x4(%rsp)
  jg     L9
  jmp    L157
  nopl   0x0(%rax)
L121:
  mov    %eax,0x24(%rsp)
L141:
  mov    %r14d,%esi
  mov    %r12d,%edx
  mov    %r15,%rdi
  mov    %r14d,%ebp
  call   <part@plt>
  lea    -0x1(%rax),%r13d
  mov    %eax,%r14d
  cmp    %r13d,%ebp
  jl     L73
L16:
  cmp    %r14d,%r12d
  jg     L141
  mov    0x24(%rsp),%ebx
  jmp    L244
  nopl   0x0(%rax)
L73:
  mov    %r13d,%ebx
  mov    %ebp,%eax
L189:
  mov    %ebx,%edx
  mov    %eax,%esi
  mov    %r15,%rdi
  mov    %eax,%r13d
  call   <part@plt>
  lea    -0x1(%rax),%edx
  cmp    %edx,%r13d
  jl     L49
L64:
  cmp    %eax,%ebx
  jg     L189
  jmp    L16
  nopw   0x0(%rax,%rax,1)
L49:
  mov    %r13d,%esi
  mov    %r15,%rdi
  mov    %eax,0x3c(%rsp)
  call   <qsort>
  mov    0x3c(%rsp),%eax
  jmp    L64
```

assistant: ```c
void qsort(int a[], int l, int r) {
  int m;
  m = part(a, l, r);
  if (l < m - 1)
    qsort(a, l, m - 1);
  if (m < r)
    qsort(a, m, r);
}
```