user: What is the c source code of the assembly code below:

```asm
<quicksort>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %edx,0x20(%rsp)
  cmp    %esi,%edx
  jle    L37
  mov    %rdi,%r15
  mov    %esi,%r13d
L9:
  mov    0x20(%rsp),%edx
  mov    %r13d,%esi
  mov    %r15,%rdi
  lea    (%rdx,%r13,1),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  mov    %eax,0x24(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x14(%rsp)
  cmp    %r13d,%eax
  jle    L107
  mov    %r13d,%r14d
  mov    %r15,%r13
L55:
  mov    0x14(%rsp),%edx
  mov    %r14d,%esi
  mov    %r13,%rdi
  lea    (%rdx,%r14,1),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  mov    %eax,0x28(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x18(%rsp)
  cmp    %r14d,%eax
  jle    L154
  mov    %r14d,%eax
  mov    %r13,%r14
  mov    %eax,%r13d
L67:
  mov    0x18(%rsp),%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  lea    (%rdx,%r13,1),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  mov    %eax,0x2c(%rsp)
  sub    $0x1,%eax
  mov    %eax,0x1c(%rsp)
  cmp    %r13d,%eax
  jle    L103
L44:
  mov    0x1c(%rsp),%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  lea    (%rdx,%r13,1),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  lea    -0x1(%rax),%r12d
  mov    %eax,0x30(%rsp)
  cmp    %r13d,%r12d
  jle    L19
L47:
  lea    (%r12,%r13,1),%eax
  mov    %r12d,%edx
  mov    %r13d,%esi
  mov    %r14,%rdi
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  lea    -0x1(%rax),%ebx
  mov    %eax,%ebp
  cmp    %r13d,%ebx
  jle    L118
  mov    %r12d,0x8(%rsp)
  mov    %r14,%rax
  mov    %r13d,%r15d
  mov    %ebp,%r14d
  mov    %ebx,%r13d
  mov    %rax,%rbp
L135:
  lea    0x0(%r13,%r15,1),%eax
  mov    %r13d,%edx
  mov    %r15d,%esi
  mov    %rbp,%rdi
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  lea    -0x1(%rax),%ebx
  mov    %eax,0xc(%rsp)
  cmp    %r15d,%ebx
  jle    L143
  mov    %rbp,%r12
L170:
  lea    (%rbx,%r15,1),%eax
  mov    %ebx,%edx
  mov    %r15d,%esi
  mov    %r12,%rdi
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  lea    -0x1(%rax),%ebp
  mov    %eax,0x34(%rsp)
  cmp    %r15d,%ebp
  jle    L129
  mov    %ebx,0x10(%rsp)
  mov    %r12,%rbx
  mov    %ebp,%r12d
L84:
  lea    (%r12,%r15,1),%eax
  mov    %r12d,%edx
  mov    %r15d,%esi
  mov    %rbx,%rdi
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  lea    -0x1(%rax),%r8d
  mov    %eax,%ebp
  cmp    %r15d,%r8d
  jle    L6
L155:
  lea    (%r8,%r15,1),%eax
  mov    %r8d,%edx
  mov    %r15d,%esi
  mov    %rbx,%rdi
  mov    %eax,%ecx
  mov    %r8d,0x3c(%rsp)
  shr    $0x1f,%ecx
  add    %eax,%ecx
  sar    %ecx
  call   <partition@plt>
  mov    %r15d,%esi
  mov    %rbx,%rdi
  lea    -0x1(%rax),%edx
  mov    %eax,0x38(%rsp)
  call   <quicksort>
  mov    0x38(%rsp),%eax
  mov    0x3c(%rsp),%r8d
  lea    0x1(%rax),%r15d
  cmp    %r15d,%r8d
  jg     L155
L6:
  lea    0x1(%rbp),%r15d
  cmp    %r15d,%r12d
  jg     L84
  mov    %rbx,%r12
  mov    0x10(%rsp),%ebx
L129:
  mov    0x34(%rsp),%r15d
  add    $0x1,%r15d
  cmp    %r15d,%ebx
  jg     L170
  mov    %r12,%rbp
L143:
  mov    0xc(%rsp),%r15d
  add    $0x1,%r15d
  cmp    %r15d,%r13d
  jg     L135
  mov    %rbp,%rax
  mov    0x8(%rsp),%r12d
  mov    %r14d,%ebp
  mov    %rax,%r14
L118:
  lea    0x1(%rbp),%r13d
  cmp    %r13d,%r12d
  jg     L47
L19:
  mov    0x30(%rsp),%r13d
  add    $0x1,%r13d
  cmp    %r13d,0x1c(%rsp)
  jg     L44
L103:
  mov    0x2c(%rsp),%r13d
  add    $0x1,%r13d
  cmp    %r13d,0x18(%rsp)
  jg     L67
  mov    %r14,%r13
L154:
  mov    0x28(%rsp),%r14d
  add    $0x1,%r14d
  cmp    %r14d,0x14(%rsp)
  jg     L55
  mov    %r13,%r15
L107:
  mov    0x24(%rsp),%r13d
  add    $0x1,%r13d
  cmp    0x20(%rsp),%r13d
  jl     L9
L37:
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void quicksort(int vec[], int left, int right) {
  if (left < right) {
    int middle = (left + right) / 2;
    int newp = partition(vec, left, right, middle);
    quicksort(vec, left, newp - 1);
    quicksort(vec, newp + 1, right);
  }
}
```