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    $0x78,%rsp
  mov    %rdi,0x38(%rsp)
  mov    %esi,0x40(%rsp)
  cmp    $0x1,%esi
  jle    L4
L127:
  mov    0x38(%rsp),%rbx
  mov    0x40(%rsp),%esi
  mov    %rbx,%rdi
  call   <partition@plt>
  mov    %eax,0x50(%rsp)
  cmp    $0x1,%eax
  jle    L83
  mov    %rbx,0x18(%rsp)
  mov    %eax,0x14(%rsp)
L64:
  mov    0x18(%rsp),%rbx
  mov    0x14(%rsp),%esi
  mov    %rbx,%rdi
  call   <partition@plt>
  mov    %eax,0x54(%rsp)
  cmp    $0x1,%eax
  jle    L100
  mov    %rbx,0x20(%rsp)
  mov    %eax,0x28(%rsp)
L39:
  mov    0x20(%rsp),%rbx
  mov    0x28(%rsp),%esi
  mov    %rbx,%rdi
  call   <partition@plt>
  mov    %eax,0x58(%rsp)
  cmp    $0x1,%eax
  jle    L141
  mov    %rbx,0x30(%rsp)
  mov    %eax,0x2c(%rsp)
L167:
  mov    0x30(%rsp),%r15
  mov    0x2c(%rsp),%esi
  mov    %r15,%rdi
  call   <partition@plt>
  mov    %eax,0x5c(%rsp)
  mov    %eax,%r13d
  cmp    $0x1,%eax
  jle    L162
L79:
  mov    %r13d,%esi
  mov    %r15,%rdi
  call   <partition@plt>
  mov    %eax,%ebp
  cmp    $0x1,%eax
  jle    L169
  mov    %eax,0x4(%rsp)
  mov    %r15,%r12
  mov    %eax,%r14d
  mov    %r13d,0x10(%rsp)
  mov    %r15,0x8(%rsp)
L142:
  mov    %r14d,%esi
  mov    %r12,%rdi
  call   <partition@plt>
  mov    %eax,%ebp
  cmp    $0x1,%eax
  jle    L151
  mov    %eax,(%rsp)
  mov    %r12,%r15
L28:
  mov    (%rsp),%esi
  mov    %r15,%rdi
  call   <partition@plt>
  mov    %eax,0x60(%rsp)
  cmp    $0x1,%eax
  jle    L155
  mov    %ebp,0x44(%rsp)
  mov    %eax,%ebp
  mov    %r12,0x48(%rsp)
  mov    %r15,%r12
L157:
  mov    %ebp,%esi
  mov    %r12,%rdi
  call   <partition@plt>
  mov    %eax,%ebx
  cmp    $0x1,%eax
  jle    L49
  mov    %r12,%rdi
  mov    %ebp,%edx
  mov    %r12,%rcx
  mov    %eax,%r12d
  mov    %rdi,%rbp
L109:
  mov    %ebx,%esi
  mov    %rbp,%rdi
  mov    %rcx,0x68(%rsp)
  mov    %edx,0x64(%rsp)
  call   <partition@plt>
  mov    %rbp,%rdi
  mov    %eax,%esi
  mov    %eax,%r13d
  call   <quicksort>
  mov    %ebx,%eax
  mov    0x64(%rsp),%edx
  mov    0x68(%rsp),%rcx
  sub    %r13d,%eax
  lea    -0x1(%rax),%ebx
  movslq %r13d,%rax
  cmp    $0x1,%ebx
  lea    0x4(%rbp,%rax,4),%rbp
  jg     L109
  mov    %r12d,%ebx
  mov    %edx,%ebp
  mov    %rcx,%r12
L49:
  mov    %ebp,%eax
  sub    %ebx,%eax
  lea    -0x1(%rax),%ebp
  movslq %ebx,%rax
  lea    0x4(%r12,%rax,4),%r12
  cmp    $0x1,%ebp
  jg     L157
  mov    0x44(%rsp),%ebp
  mov    0x48(%rsp),%r12
L155:
  mov    (%rsp),%r13d
  movslq 0x60(%rsp),%rbx
  sub    %ebx,%r13d
  lea    0x4(%r15,%rbx,4),%r15
  lea    -0x1(%r13),%eax
  mov    %eax,(%rsp)
  cmp    $0x1,%eax
  jg     L28
L151:
  sub    %ebp,%r14d
  movslq %ebp,%rax
  sub    $0x1,%r14d
  lea    0x4(%r12,%rax,4),%r12
  cmp    $0x1,%r14d
  jg     L142
  mov    0x4(%rsp),%ebp
  mov    0x10(%rsp),%r13d
  mov    0x8(%rsp),%r15
L169:
  sub    %ebp,%r13d
  movslq %ebp,%rdx
  sub    $0x1,%r13d
  lea    0x4(%r15,%rdx,4),%r15
  cmp    $0x1,%r13d
  jg     L79
L162:
  mov    0x2c(%rsp),%eax
  mov    0x5c(%rsp),%edx
  mov    0x30(%rsp),%rsi
  sub    %edx,%eax
  lea    -0x1(%rax),%ecx
  movslq %edx,%rax
  lea    0x4(%rsi,%rax,4),%rax
  mov    %ecx,0x2c(%rsp)
  mov    %rax,0x30(%rsp)
  cmp    $0x1,%ecx
  jg     L167
L141:
  mov    0x58(%rsp),%edx
  mov    0x28(%rsp),%eax
  sub    %edx,%eax
  lea    -0x1(%rax),%ecx
  movslq %edx,%rax
  mov    0x20(%rsp),%rdx
  mov    %ecx,0x28(%rsp)
  lea    0x4(%rdx,%rax,4),%rax
  mov    %rax,0x20(%rsp)
  cmp    $0x1,%ecx
  jg     L39
L100:
  mov    0x14(%rsp),%eax
  mov    0x54(%rsp),%edx
  mov    0x18(%rsp),%rcx
  sub    %edx,%eax
  lea    -0x1(%rax),%esi
  movslq %edx,%rax
  lea    0x4(%rcx,%rax,4),%rax
  mov    %esi,0x14(%rsp)
  mov    %rax,0x18(%rsp)
  cmp    $0x1,%esi
  jg     L64
L83:
  mov    0x40(%rsp),%eax
  mov    0x50(%rsp),%ecx
  mov    0x38(%rsp),%rsi
  sub    %ecx,%eax
  lea    -0x1(%rax),%edi
  movslq %ecx,%rax
  lea    0x4(%rsi,%rax,4),%rax
  mov    %edi,0x40(%rsp)
  mov    %rax,0x38(%rsp)
  cmp    $0x1,%edi
  jg     L127
L4:
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void quicksort(int *a, int n) {
  int pindex;
  if (n <= 1)
    return;
  else {
    pindex = partition(a, n);
    quicksort(a, pindex);
    quicksort(a + pindex + 1, n - pindex - 1);
  }
}
```