user: 请将以下的汇编代码转换成C语言代码：

```asm
<merge>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x18,%rsp
  mov    %rdi,%r9
  mov    %edx,%edi
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  mov    %edx,%ebx
  sub    %esi,%ebx
  lea    0x1(%rbx),%r12d
  sub    %edx,%ecx
  mov    %ecx,%r11d
  movslq %r12d,%rax
  lea    0xf(,%rax,4),%rax
  mov    %rax,%rcx
  and    $0xfffffffffffffff0,%rcx
  and    $0xfffffffffffff000,%rax
  mov    %rsp,%rdx
  sub    %rax,%rdx
L118:
  cmp    %rdx,%rsp
  je     L43
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L118
L43:
  mov    %rcx,%rax
  and    $0xfff,%eax
  sub    %rax,%rsp
  test   %rax,%rax
  je     L144
  orq    $0x0,-0x8(%rsp,%rax,1)
L144:
  mov    %rsp,%r8
  movslq %r11d,%rax
  lea    0xf(,%rax,4),%rax
  mov    %rax,%rcx
  and    $0xfffffffffffffff0,%rcx
  and    $0xfffffffffffff000,%rax
  mov    %rsp,%rdx
  sub    %rax,%rdx
L238:
  cmp    %rdx,%rsp
  je     L0
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L238
L0:
  mov    %rcx,%rax
  and    $0xfff,%eax
  sub    %rax,%rsp
  test   %rax,%rax
  je     L123
  orq    $0x0,-0x8(%rsp,%rax,1)
L123:
  mov    %rsp,%r10
  test   %r12d,%r12d
  jle    L20
  mov    %ebx,%r13d
  mov    $0x0,%eax
  movslq %esi,%rcx
  add    %r9,%rcx
L29:
  movsbl (%rcx,%rax,1),%edx
  mov    %edx,(%r8,%rax,4)
  mov    %rax,%rdx
  add    $0x1,%rax
  cmp    %r13,%rdx
  jne    L29
L20:
  test   %r11d,%r11d
  jle    L69
  lea    0x1(%r11),%r13d
  mov    $0x1,%eax
  movslq %edi,%rcx
  add    %r9,%rcx
L155:
  movsbl (%rcx,%rax,1),%edx
  mov    %edx,-0x4(%r10,%rax,4)
  add    $0x1,%rax
  cmp    %r13,%rax
  jne    L155
  test   %r12d,%r12d
  jle    L231
  lea    0x1(%rsi),%edi
  movslq %esi,%rcx
  add    %r9,%rcx
  mov    $0x0,%edx
  mov    $0x0,%eax
  jmp    L70
L187:
  mov    %sil,(%rcx)
  mov    %edi,%esi
  add    $0x1,%edx
L173:
  add    $0x1,%edi
  add    $0x1,%rcx
  cmp    %r12d,%eax
  jge    L235
  cmp    %r11d,%edx
  jge    L235
L70:
  movslq %eax,%rsi
  mov    (%r8,%rsi,4),%r13d
  movslq %edx,%rsi
  mov    (%r10,%rsi,4),%esi
  cmp    %esi,%r13d
  jge    L187
  mov    %r13b,(%rcx)
  mov    %edi,%esi
  add    $0x1,%eax
  jmp    L173
L235:
  cmp    %r12d,%eax
  jge    L169
L12:
  movslq %eax,%rcx
  mov    %eax,%r12d
  mov    %ebx,%edi
  sub    %eax,%edi
  lea    0x1(%rcx,%rdi,1),%r13
  mov    %rcx,%rax
  movslq %esi,%rdi
  sub    %rcx,%rdi
  add    %r9,%rdi
L59:
  mov    (%r8,%rax,4),%ecx
  mov    %cl,(%rdi,%rax,1)
  add    $0x1,%rax
  cmp    %r13,%rax
  jne    L59
  lea    0x1(%rbx,%rsi,1),%esi
  sub    %r12d,%esi
L169:
  cmp    %r11d,%edx
  jge    L38
  movslq %edx,%rdx
  mov    %rdx,%rax
  movslq %esi,%rsi
  sub    %rdx,%rsi
  add    %r9,%rsi
L79:
  mov    (%r10,%rax,4),%edx
  mov    %dl,(%rsi,%rax,1)
  add    $0x1,%rax
  cmp    %eax,%r11d
  jg     L79
L38:
  mov    -0x28(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L18
  lea    -0x18(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %rbp
  ret
L231:
  mov    $0x0,%edx
  jmp    L169
L69:
  mov    $0x0,%edx
  mov    $0x0,%eax
  test   %r12d,%r12d
  jg     L12
  jmp    L38
L18:
  call   <__stack_chk_fail@plt>
```

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++;
  }
}
```