user: What would the C source look like for the assembly code provided here:

```asm
<merge>:
  endbr64
  push   %rbp
  movslq %edx,%r11
  sub    %r11d,%ecx
  mov    %ecx,%r9d
  mov    %rsp,%rbp
  push   %r13
  push   %r12
  push   %rbx
  mov    %r11d,%ebx
  sub    %esi,%ebx
  lea    0x1(%rbx),%r10d
  sub    $0x18,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  movslq %r10d,%rax
  mov    %rsp,%rcx
  lea    0xf(,%rax,4),%rax
  mov    %rax,%rdx
  and    $0xfffffffffffff000,%rax
  sub    %rax,%rcx
  and    $0xfffffffffffffff0,%rdx
  cmp    %rcx,%rsp
  je     L249
L146:
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  cmp    %rcx,%rsp
  jne    L146
L249:
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  jne    L224
L0:
  movslq %r9d,%rax
  mov    %rsp,%r8
  mov    %rsp,%rcx
  lea    0xf(,%rax,4),%rax
  mov    %rax,%rdx
  and    $0xfffffffffffff000,%rax
  sub    %rax,%r8
  and    $0xfffffffffffffff0,%rdx
  cmp    %r8,%rsp
  je     L68
L93:
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  cmp    %r8,%rsp
  jne    L93
L68:
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  jne    L117
L64:
  movslq %esi,%r12
  mov    %rsp,%r8
  mov    %ebx,%r13d
  xor    %eax,%eax
  add    %rdi,%r12
  test   %r10d,%r10d
  jle    L118
  nopl   0x0(%rax)
L151:
  movsbl (%r12,%rax,1),%edx
  mov    %edx,(%rcx,%rax,4)
  mov    %rax,%rdx
  add    $0x1,%rax
  cmp    %r13,%rdx
  jne    L151
L118:
  test   %r9d,%r9d
  jle    L185
  lea    0x1(%r9),%r12d
  mov    $0x1,%eax
  add    %rdi,%r11
  nopl   0x0(%rax)
L157:
  movsbl (%r11,%rax,1),%edx
  mov    %edx,-0x4(%r8,%rax,4)
  add    $0x1,%rax
  cmp    %r12,%rax
  jne    L157
  test   %r10d,%r10d
  jle    L235
  lea    0x1(%rsi),%r12d
  xor    %eax,%eax
  xor    %r11d,%r11d
  movslq %r12d,%r12
  jmp    L180
  nopw   0x0(%rax,%rax,1)
L236:
  mov    %r13d,%edx
  add    $0x1,%r11d
  mov    %dl,-0x1(%rdi,%r12,1)
  add    $0x1,%r12
  cmp    %r10d,%r11d
  jge    L262
L28:
  cmp    %r9d,%eax
  jge    L220
L180:
  movslq %r11d,%rdx
  mov    %r12d,%esi
  mov    (%rcx,%rdx,4),%r13d
  movslq %eax,%rdx
  mov    (%r8,%rdx,4),%edx
  cmp    %edx,%r13d
  jl     L236
  mov    %dl,-0x1(%rdi,%r12,1)
  add    $0x1,%eax
  add    $0x1,%r12
  cmp    %r10d,%r11d
  jl     L28
  nopl   (%rax)
L262:
  cmp    %r9d,%eax
  jge    L24
L231:
  cltq
  movslq %esi,%r12
  sub    %rax,%r12
  add    %r12,%rdi
  nopl   0x0(%rax,%rax,1)
L122:
  mov    (%r8,%rax,4),%edx
  mov    %dl,(%rdi,%rax,1)
  add    $0x1,%rax
  cmp    %eax,%r9d
  jg     L122
L24:
  mov    -0x28(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L102
  lea    -0x18(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %rbp
  ret
  nopw   0x0(%rax,%rax,1)
L224:
  orq    $0x0,-0x8(%rsp,%rdx,1)
  jmp    L0
  nopl   0x0(%rax,%rax,1)
L220:
  cmp    %r10d,%r11d
  jge    L262
L219:
  movslq %r11d,%rdx
  movslq %esi,%r12
  sub    %r11d,%ebx
  sub    %rdx,%r12
  lea    0x1(%rdx,%rbx,1),%r13
  add    %rdi,%r12
  nopl   0x0(%rax)
L260:
  mov    (%rcx,%rdx,4),%ebx
  mov    %bl,(%r12,%rdx,1)
  add    $0x1,%rdx
  cmp    %rdx,%r13
  jne    L260
  add    %esi,%r10d
  mov    %r10d,%esi
  sub    %r11d,%esi
  jmp    L262
  xchg   %ax,%ax
L185:
  xor    %eax,%eax
  xor    %r11d,%r11d
  test   %r10d,%r10d
  jg     L219
  jmp    L24
L117:
  orq    $0x0,-0x8(%rsp,%rdx,1)
  jmp    L64
L102:
  call   <__stack_chk_fail@plt>
L235:
  xor    %eax,%eax
  jmp    L231
```

assistant: ```c
void merge(char *str, int start, int mid, int high) {
  int n1 = mid - start + 1;
  int n2 = high - mid;
  int L[n1], R[n2];
  int i, j, k;
  for (i = 0; i < n1; i++) {
    L[i] = str[start + i];
  }
  for (i = 0; i < n2; i++) {
    R[i] = str[mid + i + 1];
  }
  i = 0, j = 0, k = start;
  while (i < n1 && j < n2) {
    if (L[i] < R[j]) {
      str[k] = L[i];
      k++;
      i++;
    } else {
      str[k] = R[j];
      k++;
      j++;
    }
  }
  while (i < n1) {
    str[k] = L[i];
    k++;
    i++;
  }
  while (j < n2) {
    str[k] = R[j];
    k++;
    j++;
  }
}
```