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

```asm
<mergeSort>:
  endbr64
  cmp    %edx,%esi
  jl     L51
  ret
  nopl   0x0(%rax)
L51:
  lea    (%rsi,%rdx,1),%eax
  push   %r15
  push   %r14
  mov    %rdi,%r14
  push   %r13
  mov    %eax,%r13d
  push   %r12
  shr    $0x1f,%r13d
  mov    %edx,%r12d
  push   %rbp
  add    %eax,%r13d
  mov    %esi,%ebp
  push   %rbx
  sar    %r13d
  mov    %rcx,%rbx
  sub    $0x18,%rsp
  cmp    %r13d,%esi
  jl     L2
  lea    0x1(%r13),%r15d
  cmp    %r12d,%r15d
  jl     L103
L127:
  add    $0x18,%rsp
  mov    %rbx,%r8
  mov    %r12d,%ecx
  mov    %r13d,%edx
  pop    %rbx
  mov    %ebp,%esi
  mov    %r14,%rdi
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    1050 <mergeArray@plt>
  nopl   0x0(%rax,%rax,1)
L2:
  lea    (%rsi,%r13,1),%eax
  mov    %eax,%r15d
  shr    $0x1f,%r15d
  add    %eax,%r15d
  sar    %r15d
  cmp    %r15d,%esi
  jl     L66
L49:
  lea    0x1(%r15),%r9d
  cmp    %r9d,%r13d
  jg     L116
L98:
  mov    %r15d,%edx
  mov    %rbx,%r8
  mov    %r13d,%ecx
  mov    %ebp,%esi
  mov    %r14,%rdi
  lea    0x1(%r13),%r15d
  call   <mergeArray@plt>
  cmp    %r12d,%r15d
  jge    L127
L103:
  lea    (%r15,%r12,1),%eax
  mov    %eax,%r9d
  shr    $0x1f,%r9d
  add    %eax,%r9d
  sar    %r9d
  cmp    %r9d,%r15d
  jl     L79
L82:
  lea    0x1(%r9),%r10d
  cmp    %r10d,%r12d
  jg     L126
L43:
  mov    %rbx,%r8
  mov    %r12d,%ecx
  mov    %r9d,%edx
  mov    %r15d,%esi
  mov    %r14,%rdi
  call   <mergeArray@plt>
  jmp    L127
  nopl   0x0(%rax,%rax,1)
L66:
  lea    (%rsi,%r15,1),%eax
  mov    %eax,%r9d
  shr    $0x1f,%r9d
  add    %eax,%r9d
  sar    %r9d
  mov    %r9d,%edx
  mov    %r9d,0x4(%rsp)
  call   <mergeSort>
  mov    0x4(%rsp),%r9d
  mov    %rbx,%rcx
  mov    %r15d,%edx
  mov    %r14,%rdi
  lea    0x1(%r9),%esi
  call   <mergeSort>
  mov    0x4(%rsp),%edx
  mov    %rbx,%r8
  mov    %r15d,%ecx
  mov    %ebp,%esi
  mov    %r14,%rdi
  call   <mergeArray@plt>
  jmp    L49
  xchg   %ax,%ax
L126:
  lea    (%r12,%r10,1),%eax
  mov    %r10d,%esi
  mov    %rbx,%rcx
  mov    %r14,%rdi
  mov    %eax,%r11d
  mov    %r9d,0xc(%rsp)
  shr    $0x1f,%r11d
  mov    %r10d,0x8(%rsp)
  add    %eax,%r11d
  sar    %r11d
  mov    %r11d,%edx
  mov    %r11d,0x4(%rsp)
  call   <mergeSort>
  mov    0x4(%rsp),%r11d
  mov    %rbx,%rcx
  mov    %r12d,%edx
  mov    %r14,%rdi
  lea    0x1(%r11),%esi
  call   <mergeSort>
  mov    0x4(%rsp),%edx
  mov    0x8(%rsp),%esi
  mov    %rbx,%r8
  mov    %r12d,%ecx
  mov    %r14,%rdi
  call   <mergeArray@plt>
  mov    0xc(%rsp),%r9d
  jmp    L43
  nopl   0x0(%rax,%rax,1)
L79:
  lea    (%r15,%r9,1),%eax
  mov    %rbx,%rcx
  mov    %r15d,%esi
  mov    %r14,%rdi
  mov    %eax,%r10d
  mov    %r9d,0xc(%rsp)
  shr    $0x1f,%r10d
  add    %eax,%r10d
  sar    %r10d
  mov    %r10d,%edx
  mov    %r10d,0x4(%rsp)
  call   <mergeSort>
  mov    0x4(%rsp),%r10d
  mov    %rbx,%rcx
  mov    %r14,%rdi
  mov    0xc(%rsp),%r9d
  lea    0x1(%r10),%esi
  mov    %r10d,0x8(%rsp)
  mov    %r9d,%edx
  mov    %r9d,0x4(%rsp)
  call   <mergeSort>
  mov    0x4(%rsp),%ecx
  mov    0x8(%rsp),%edx
  mov    %rbx,%r8
  mov    %r15d,%esi
  mov    %r14,%rdi
  call   <mergeArray@plt>
  mov    0x4(%rsp),%r9d
  jmp    L82
  nopw   0x0(%rax,%rax,1)
L116:
  lea    0x0(%r13,%r9,1),%eax
  mov    %r9d,%esi
  mov    %rbx,%rcx
  mov    %r14,%rdi
  mov    %eax,%r10d
  mov    %r9d,0x8(%rsp)
  shr    $0x1f,%r10d
  add    %eax,%r10d
  sar    %r10d
  mov    %r10d,%edx
  mov    %r10d,0x4(%rsp)
  call   <mergeSort>
  mov    0x4(%rsp),%r10d
  mov    %rbx,%rcx
  mov    %r13d,%edx
  mov    %r14,%rdi
  lea    0x1(%r10),%esi
  call   <mergeSort>
  mov    0x4(%rsp),%edx
  mov    0x8(%rsp),%esi
  mov    %rbx,%r8
  mov    %r13d,%ecx
  mov    %r14,%rdi
  call   <mergeArray@plt>
  jmp    L98
```

assistant: ```c
void mergeSort(int a[], int first, int last, int temp[]) {
  if (first < last) {
    int mid = (first + last) / 2;
    mergeSort(a, first, mid, temp);
    mergeSort(a, mid + 1, last, temp);
    mergeArray(a, first, mid, last, temp);
  }
}
```